fix unit test failures in GitHub Actions caused by missing gitconfig

.github/actions/check/Dockerfile

@@ -1,5 +1,7 @@
 FROM golangci/golangci-lint:v1.12.5
 
+RUN apt-get install git
+
 LABEL "com.github.actions.name"="Check"
 LABEL "com.github.actions.description"="Run static analysis and unit tests"
 LABEL "com.github.actions.icon"="check-circle"
@@ -9,4 +11,4 @@ COPY "entrypoint.sh" "/entrypoint.sh"
 RUN chmod +x /entrypoint.sh
 
 ENV GOFLAGS -mod=vendor
-ENTRYPOINT ["/entrypoint.sh"]
+ENTRYPOINT ["/entrypoint.sh"]