Clean up post-move, add a README

.gitlab-ci.yml

-include: "https://git.autistici.org/ai3/build-container/raw/master/common.yml"
+include: "https://git.autistici.org/pipelines/containers/raw/master/common.yml"
 

Dockerfile

 FROM golang:1.20
 
 WORKDIR /tmp
-COPY run-go-test /usr/bin/run-go-test
+COPY --chmod=0755 run-go-test /usr/bin/run-go-test
 RUN go install github.com/boumenot/gocover-cobertura@latest ; \
-    go install github.com/jstemmer/go-junit-report@latest ; \
-    chmod 0755 /usr/bin/run-go-test
-
+    go install github.com/jstemmer/go-junit-report@latest

README.md

+Golang test container image
+===
+
+This repository builds a container image suitable for running Go
+tests. Some useful features:
+
+* generate Gitlab-compatible test and coverage report artifacts
+* properly aggregate coverage data for a whole project (across all its
+  sub-packages)
+
+To use, include *ci.yml* from your project's *.gitlab-ci.yml*. Some
+useful variables that can be defined:
+
+* `GO_TEST_PACKAGES` - Debian packages to install before running the
+  tests
+* `GO_TEST_GENERATE` - Set to a non-empty value to run "go generate
+  ./..." before running the tests
+* `GO_TEST_ARGS` - Additional arguments for "go test" (tags, etc)
+

ci.yml

 go_test:
   stage: test
-  image: registry.git.autistici.org/ai3/docker/test/golang:master
+  image: registry.git.autistici.org/pipelines/images/test/golang:master
   script:
     - if [ -n "$GO_TEST_PACKAGES" ]; then apt-get -q update; env DEBIAN_FRONTEND=noninteractive apt-get -qy install --no-install-recommends $GO_TEST_PACKAGES; fi
     - if [ -n "$GO_TEST_GENERATE" ]; then go generate ./... ; fi