Add deprecation notice to README.md

[qmonnet]

We plan to decommission this repository, let's add a note at the top of the README.md to indicate why.

[github-actions]

Outdated packages (gnu64):

priority	nix_package	version_local	version_nixpkgs	version_upstream
15	libunistring	1.4.1	1.4.1	1.4.2
13	glibc	2.42-51	2.42	2.43
12	libxml2	2.15.1	2.15.1	2.15.2
11	llvm	21.1.8	21.1.8	22.1.2
11	llvm	21.1.8	22.1.0-rc3	22.1.2
11	binutils	2.44	2.44	2.46.0;2.46
10	pcre2	10.46	10.46	10.47
5	perl	5.42.0	5.42.0	5.42.1
4	kmod	31	31	34.2
4	expat	2.7.4	2.7.4	2.7.5
4	sqlite	3.51.2	3.51.2	3.51.3
4	numactl	2.0.18	2.0.18	2.0.19
2	dpdk	25.07	25.07	25.11

[github-actions]

Vulnerable packages (gnu64):

vuln_id	url	package	severity	version_local	version_nixpkgs	version_upstream	package_repology	sortcol	classify
CVE-2026-27171	https://nvd.nist.gov/vuln/detail/CVE-2026-27171	zlib	2.9	1.3.1	1.3.2	1.3.2	zlib	2026A0000027171	fix_update_to_version_nixpkgs
CVE-2026-22184	https://nvd.nist.gov/vuln/detail/CVE-2026-22184	zlib	7.8	1.3.1	1.3.2	1.3.2	zlib	2026A0000022184	fix_update_to_version_nixpkgs
CVE-2026-4647	https://nvd.nist.gov/vuln/detail/CVE-2026-4647	binutils	6.1	2.44	2.44	2.46.0	binutils	2026A0000004647	err_not_vulnerable_based_on_repology
CVE-2026-3442	https://nvd.nist.gov/vuln/detail/CVE-2026-3442	binutils	7.1	2.44	2.44	2.46.0	binutils	2026A0000003442	err_not_vulnerable_based_on_repology
CVE-2026-3441	https://nvd.nist.gov/vuln/detail/CVE-2026-3441	binutils	7.1	2.44	2.44	2.46.0	binutils	2026A0000003441	err_not_vulnerable_based_on_repology
CVE-2026-2673	https://nvd.nist.gov/vuln/detail/CVE-2026-2673	openssl	7.5	3.6.1	3.6.1	3.6.1	openssl	2026A0000002673	err_not_vulnerable_based_on_repology
OSV-2026-350	https://osv.dev/OSV-2026-350	binutils		2.44	2.44	2.46.0	binutils	2026A0000000350	err_not_vulnerable_based_on_repology
CVE-2025-69652	https://nvd.nist.gov/vuln/detail/CVE-2025-69652	binutils	6.2	2.44	2.44	2.46.0	binutils	2025A0000069652	fix_not_available
CVE-2025-69651	https://nvd.nist.gov/vuln/detail/CVE-2025-69651	binutils	5.5	2.44	2.44	2.46.0	binutils	2025A0000069651	fix_not_available
CVE-2025-69650	https://nvd.nist.gov/vuln/detail/CVE-2025-69650	binutils	7.5	2.44	2.44	2.46.0	binutils	2025A0000069650	fix_not_available
CVE-2025-69649	https://nvd.nist.gov/vuln/detail/CVE-2025-69649	binutils	7.5	2.44	2.44	2.46.0	binutils	2025A0000069649	fix_not_available
CVE-2025-69648	https://nvd.nist.gov/vuln/detail/CVE-2025-69648	binutils	6.2	2.44	2.44	2.46.0	binutils	2025A0000069648	fix_update_to_version_upstream
CVE-2025-69647	https://nvd.nist.gov/vuln/detail/CVE-2025-69647	binutils	6.2	2.44	2.44	2.46.0	binutils	2025A0000069647	fix_update_to_version_upstream
CVE-2025-69646	https://nvd.nist.gov/vuln/detail/CVE-2025-69646	binutils	5.5	2.44	2.44	2.46.0	binutils	2025A0000069646	fix_update_to_version_upstream
CVE-2025-69645	https://nvd.nist.gov/vuln/detail/CVE-2025-69645	binutils	5.5	2.44	2.44	2.46.0	binutils	2025A0000069645	fix_update_to_version_upstream
CVE-2025-69644	https://nvd.nist.gov/vuln/detail/CVE-2025-69644	binutils	5.0	2.44	2.44	2.46.0	binutils	2025A0000069644	fix_update_to_version_upstream
CVE-2025-15281	https://nvd.nist.gov/vuln/detail/CVE-2025-15281	glibc	7.5	2.42-51	2.42	2.43	glibc	2025A0000015281	fix_update_to_version_upstream
CVE-2025-8225	https://nvd.nist.gov/vuln/detail/CVE-2025-8225	binutils	3.3	2.44	2.44	2.46.0	binutils	2025A0000008225	fix_update_to_version_upstream
CVE-2025-8224	https://nvd.nist.gov/vuln/detail/CVE-2025-8224	binutils	3.3	2.44	2.44	2.46.0	binutils	2025A0000008224	fix_update_to_version_upstream
CVE-2025-6170	https://nvd.nist.gov/vuln/detail/CVE-2025-6170	libxml2	2.5	2.15.1	2.15.1	2.15.2	libxml2	2025A0000006170	err_not_vulnerable_based_on_repology
CVE-2025-6021	https://nvd.nist.gov/vuln/detail/CVE-2025-6021	libxml2	7.5	2.15.1	2.15.1	2.15.2	libxml2	2025A0000006021	err_not_vulnerable_based_on_repology
CVE-2025-3198	https://nvd.nist.gov/vuln/detail/CVE-2025-3198	binutils	3.3	2.44	2.44	2.46.0	binutils	2025A0000003198	fix_update_to_version_upstream
CVE-2025-1153	https://nvd.nist.gov/vuln/detail/CVE-2025-1153	binutils	3.1	2.44	2.44	2.46.0	binutils	2025A0000001153	fix_update_to_version_upstream
OSV-2024-698	https://osv.dev/OSV-2024-698	libxml2		2.15.1	2.15.1	2.15.2	libxml2	2024A0000000698	err_not_vulnerable_based_on_repology
CVE-2023-6992	https://nvd.nist.gov/vuln/detail/CVE-2023-6992	zlib	4.0	1.3.1	1.3.2	1.3.2	zlib	2023A0000006992	err_not_vulnerable_based_on_repology
CVE-2023-4039	https://nvd.nist.gov/vuln/detail/CVE-2023-4039	gcc	4.8	15.2.0	15.2.0	15.2.0	gcc	2023A0000004039	fix_not_available
OSV-2021-777	https://osv.dev/OSV-2021-777	libxml2		2.15.1	2.15.1	2.15.2	libxml2	2021A0000000777	err_not_vulnerable_based_on_repology
CVE-2016-2781	https://nvd.nist.gov/vuln/detail/CVE-2016-2781	coreutils	6.5	9.10	9.10	9.10	coreutils	2016A0000002781	fix_not_available