chmod executables when copying to the docker (#17423)

Run chmod on the executables and the entrypoint when copying them to the
docker in dockerfile.

Signed-off-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: Norwin <noerw@users.noreply.github.com>
Co-authored-by: delvh <dev.lh@web.de>

Dockerfile

 COPY docker/root /
 COPY --from=build-env /go/src/code.gitea.io/gitea/gitea /app/gitea/gitea
 COPY --from=build-env /go/src/code.gitea.io/gitea/environment-to-ini /usr/local/bin/environment-to-ini
+RUN chmod 755 /usr/bin/entrypoint /app/gitea/gitea /usr/local/bin/environment-to-ini
+RUN chmod 755 /etc/s6/gitea/* /etc/s6/openssh/* /etc/s6/.s6-svscan/*
 RUN ln -s /app/gitea/gitea /usr/local/bin/gitea

Dockerfile.rootless

 ARG GITEA_VERSION
 ARG TAGS="sqlite sqlite_unlock_notify"
 ENV TAGS "bindata timetzdata $TAGS"
-ARG CGO_EXTRA_CFLAGS 
+ARG CGO_EXTRA_CFLAGS
 
 #Build deps
 RUN apk --no-cache add build-base git nodejs npm
 COPY docker/rootless /
 COPY --from=build-env --chown=root:root /go/src/code.gitea.io/gitea/gitea /usr/local/bin/gitea
 COPY --from=build-env --chown=root:root /go/src/code.gitea.io/gitea/environment-to-ini /usr/local/bin/environment-to-ini
+RUN chmod 755 /usr/local/bin/docker-entrypoint.sh /app/gitea/gitea /usr/local/bin/environment-to-ini /usr/local/bin/docker-setup.sh
 
 #git:git
 USER 1000:1000