[CI] implementation: forgejo container images

(cherry picked from commit dd1971d4e60f37fb76daeb6cef8b1defcc957a34)
(cherry picked from commit 3981dbaf8c0dd74b0e82a7afc36809998ac775a2)

Dockerfile

@@ -24,7 +24,7 @@ RUN if [ -n "${GITEA_VERSION}" ]; then git checkout "${GITEA_VERSION}"; fi \
 RUN go build contrib/environment-to-ini/environment-to-ini.go
 
 FROM alpine:3.17
-LABEL maintainer="maintainers@gitea.io"
+LABEL maintainer="contact@forgejo.org"
 
 EXPOSE 22 3000
 

Dockerfile.rootless

@@ -24,7 +24,7 @@ RUN if [ -n "${GITEA_VERSION}" ]; then git checkout "${GITEA_VERSION}"; fi \
 RUN go build contrib/environment-to-ini/environment-to-ini.go
 
 FROM alpine:3.17
-LABEL maintainer="maintainers@gitea.io"
+LABEL maintainer="contact@forgejo.org"
 
 EXPOSE 2222 3000