Add newly generated PSBTs to cache

[dr-orlovsky]

Counterpart for BP-WG/bp-std#59

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 64 lines in your changes missing coverage. Please review.

Project coverage is 4.7%. Comparing base (b639538) to head (bf4f282).
Report is 3 commits behind head on v0.12.

Files with missing lines	Patch %	Lines
src/wallet.rs	0.0%	64 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff           @@
##           v0.12    #87     +/-   ##
======================================
- Coverage    4.9%   4.7%   -0.1%     
======================================
  Files         24     24             
  Lines       2257   2321     +64     
======================================
  Hits         110    110             
- Misses      2147   2211     +64     

Flag	Coverage Δ
rust	4.7% <0.0%> (-0.1%)	⬇️

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