Try to fix pack acceptance, continued

Use a released version of pack when running pack acceptance (avoids v0.28.0-rc1).

In lifecycle CI, pack acceptance tests are failing on Windows when the pack version is v0.28.0-rc1.
The previous commit, which attempted to make lifecycle CI match pack CI by using go 1.17,
  did not fix the issue.
It was manually confirmed on a Windows dev worker that pack acceptance passes
  with the same pack version and the same lifecycle version that are failing in CI.
Therefore, the failling tests do not appear to relate to the lifecycle,
  and are instead likely due to other unknown differences in the CI environments that should be determined later.

Signed-off-by: Natalie Arellano <narellano@vmware.com>

.github/workflows/build.yml

@@ -262,7 +262,7 @@ jobs:
       - name: Run pack acceptance
         run: |
           cd pack
-          git checkout $(git describe --abbrev=0 --tags) # check out the latest tag
+          git checkout $(git describe --abbrev=0 --tags  --exclude *-rc*) # check out the latest tag
           LIFECYCLE_PATH="../lifecycle-v${{ env.LIFECYCLE_VERSION }}+linux.x86-64.tgz" \
           LIFECYCLE_IMAGE="buildpacksio/lifecycle:${{ env.LIFECYCLE_IMAGE_TAG }}" \
           make acceptance
@@ -328,7 +328,7 @@ jobs:
       - name: Run pack acceptance
         run: |
           cd pack
-          git checkout $(git describe --abbrev=0 --tags) # check out the latest tag
+          git checkout $(git describe --abbrev=0 --tags  --exclude *-rc*) # check out the latest tag
           $env:LIFECYCLE_PATH="..\lifecycle-v${{ env.LIFECYCLE_VERSION }}+windows.x86-64.tgz"
           $env:LIFECYCLE_IMAGE="buildpacksio/lifecycle:${{ env.LIFECYCLE_IMAGE_TAG }}"
           make acceptance

acceptance/extender_test.go

@@ -133,6 +133,7 @@ func testExtenderFunc(platformAPI string) func(t *testing.T, when spec.G, it spe
 					h.AssertStringContains(t, firstOutput, "Hello Extensions buildpack\ncurl") // output by buildpack, shows that curl was installed on the build image
 					t.Log("sets environment variables from the extended build image in the build context")
 					h.AssertStringContains(t, firstOutput, "CNB_STACK_ID for buildpack: stack-id-from-ext-tree")
+					h.AssertStringContains(t, firstOutput, "HOME for buildpack: /home/cnb")
 
 					t.Log("cleans the kaniko directory")
 					fis, err := os.ReadDir(kanikoDir)

acceptance/testdata/extender/Dockerfile

@@ -1,3 +1,12 @@
 FROM ubuntu:bionic
 
+ARG cnb_uid=1234
+ARG cnb_gid=1000
+
+ENV CNB_USER_ID=${cnb_uid}
+ENV CNB_GROUP_ID=${cnb_gid}
+
 COPY ./container/ /
+
+RUN groupadd cnb --gid ${cnb_gid} && \
+  useradd --uid ${cnb_uid} --gid ${cnb_gid} -m -s /bin/bash cnb

acceptance/testdata/extender/container/cnb/buildpacks/samples_hello-extensions/0.0.1/bin/build

@@ -7,3 +7,4 @@ curl --version
 tree /layers
 
 echo "CNB_STACK_ID for buildpack: ${CNB_STACK_ID}"
+echo "HOME for buildpack: ${HOME}"

cmd/lifecycle/extender.go

@@ -75,6 +75,9 @@ func (e *extendCmd) Exec() error {
 	if err = priv.RunAs(e.UID, e.GID); err != nil {
 		return cmd.FailErr(err, fmt.Sprintf("exec as user %d:%d", e.UID, e.GID))
 	}
+	if err = priv.SetEnvironmentForUser(e.UID); err != nil {
+		return cmd.FailErr(err, fmt.Sprintf("set environment for user %d", e.UID))
+	}
 	buildCmd := buildCmd{
 		groupPath: e.GroupPath,
 		planPath:  e.PlanPath,