ci(l2): specify fixtures paths for l2 workflow (#5508)

**Motivation**
The l2 ci runs on any change in the fixture directory, we want it to run
on certain paths.
<!-- Why does this pull request exist? What are its goals? -->

**Description**
Specify which paths under fixtures the l2 ci should run on.
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introduces -->

<!-- Link to issues: Resolves #111, Resolves #222 -->

Author: gianbelinche

.github/workflows/pr-main_l2.yaml

@@ -31,7 +31,13 @@ jobs:
           filters: |
             run_tests:
               - "crates/l2/**"
-              - "fixtures/**"
+              - "fixtures/keys/**"
+              - "fixtures/genesis/l1-dev.json"
+              - "fixtures/genesis/l2.json"
+              - "fixtures/cache/**"
+              - "fixtures/blobs/**"
+              - "fixtures/blockchain/**"
+              - "fixtures/contracts/**"
               - "crates/blockchain/dev/**"
               - "crates/vm/levm/**"
               - ".github/workflows/pr-main_l2.yaml"