fix(oidc): image parse sha support

[plyr4]

tiny fix for #1172 invalid reference format with sha tags

or should we use reference.Parse similar to the worker code

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 56.17%. Comparing base (67a8e47) to head (d10993f).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1207   +/-   ##
=======================================
  Coverage   56.16%   56.17%           
=======================================
  Files         584      584           
  Lines       21288    21291    +3     
=======================================
+ Hits        11957    11960    +3     
  Misses       8717     8717           
  Partials      614      614           

Files with missing lines	Coverage Δ
internal/token/mint.go	25.47% <100.00%> (+2.17%)	⬆️

[ecrupper]

TODO may be to actually parse the SHA and make it a claim. Not all SHA digests are going to refer to latest