fix: update help doc

[JeyJeyGao]

Fix:

• update the link to plugin-extensibility.md to be v1.0.0

Resolves #128
Signed-off-by: Junjie Gao [email protected]

[codecov]

Codecov Report

Merging #130 (84af6d8) into main (a685a90) will decrease coverage by 0.77%.
Report is 1 commits behind head on main.
The diff coverage is 84.61%.

@@            Coverage Diff             @@
##             main     #130      +/-   ##
==========================================
- Coverage   94.19%   93.42%   -0.77%     
==========================================
  Files          15       16       +1     
  Lines         465      502      +37     
==========================================
+ Hits          438      469      +31     
- Misses         27       33       +6     

Files Changed	Coverage Δ
...ugin.AzureKeyVault/Certificate/CertificateChain.cs	100.00% <ø> (ø)
...on.Plugin.AzureKeyVault/KeyVault/KeyVaultClient.cs	86.20% <53.84%> (-5.80%)	⬇️
...otation.Plugin.AzureKeyVault/Certificate/Pkcs12.cs	100.00% <100.00%> (ø)
Notation.Plugin.AzureKeyVault/Program.cs	76.92% <100.00%> (ø)

[shizhMSFT]

LGTM