fix(entrypoint.sh): add gpg.program

Add `gpg.program` to Git config.

Author: Hendry, Adam

entrypoint.sh

@@ -20,9 +20,11 @@ if [[ $INPUT_GPG_SIGN == 'true' ]]; then
     exit 2
   fi
   echo "Configuring GPG for signing commits and tags..."
+  git config --local gpg.program gpg
   git config --local commit.gpgsign true
   git config --local tag.gpgsign true
   git config --local user.signingkey "${INPUT_GIT_SIGNINGKEY}"
+  echo "Git GPG program: $(git config --get gpg.program)"
   echo "Git sign commits?: $(git config --get commit.gpgsign)"
   echo "Git sign tags?: $(git config --get tag.gpgsign)"
 fi