Update GitLab provided tags (#9275)

Author: daniel-mohedano

dd-java-agent/agent-ci-visibility/src/main/java/datadog/trace/civisibility/ci/GitLabInfo.java

@@ -41,6 +41,9 @@ class GitLabInfo implements CIProviderInfo {
   public static final String GITLAB_CI_RUNNER_TAGS = "CI_RUNNER_TAGS";
   public static final String GITLAB_PULL_REQUEST_BASE_BRANCH =
       "CI_MERGE_REQUEST_TARGET_BRANCH_NAME";
+  public static final String GITLAB_PULL_REQUEST_BASE_SHA = "CI_MERGE_REQUEST_DIFF_BASE_SHA";
+  public static final String GITLAB_PULL_REQUEST_BASE_HEAD_SHA =
+      "CI_MERGE_REQUEST_TARGET_BRANCH_SHA";
   public static final String GITLAB_PULL_REQUEST_COMMIT_HEAD_SHA =
       "CI_MERGE_REQUEST_SOURCE_BRANCH_SHA";
   public static final String GITLAB_PULL_REQUEST_NUMBER = "CI_MERGE_REQUEST_IID";
@@ -88,8 +91,8 @@ public CIInfo buildCIInfo() {
   public PullRequestInfo buildPullRequestInfo() {
     return new PullRequestInfo(
         normalizeBranch(environment.get(GITLAB_PULL_REQUEST_BASE_BRANCH)),
-        null,
-        null,
+        environment.get(GITLAB_PULL_REQUEST_BASE_SHA),
+        environment.get(GITLAB_PULL_REQUEST_BASE_HEAD_SHA),
         new CommitInfo(environment.get(GITLAB_PULL_REQUEST_COMMIT_HEAD_SHA)),
         environment.get(GITLAB_PULL_REQUEST_NUMBER));
   }

dd-java-agent/agent-ci-visibility/src/test/resources/ci/gitlab.json

@@ -1080,8 +1080,10 @@
       "CI_JOB_NAME": "gitlab-job-name",
       "CI_JOB_STAGE": "gitlab-stage-name",
       "CI_JOB_URL": "https://gitlab.com/job",
+      "CI_MERGE_REQUEST_DIFF_BASE_SHA": "bf6c156e8c1ec9cf43239162bca38cad22a3f4d2",
       "CI_MERGE_REQUEST_IID": 42,
       "CI_MERGE_REQUEST_TARGET_BRANCH_NAME": "target-branch",
+      "CI_MERGE_REQUEST_TARGET_BRANCH_SHA": "eb6dda23983998409db832ad675ec18ec32a8205",
       "CI_PIPELINE_ID": "gitlab-pipeline-id",
       "CI_PIPELINE_IID": "gitlab-pipeline-number",
       "CI_PIPELINE_URL": "https://foo/repo/-/pipelines/1234",
@@ -1110,6 +1112,8 @@
       "git.commit.message": "gitlab-git-commit-message",
       "git.commit.sha": "b9f0fb3fdbb94c9d24b2c75b49663122a529e123",
       "git.pull_request.base_branch": "target-branch",
+      "git.pull_request.base_branch_head_sha": "eb6dda23983998409db832ad675ec18ec32a8205",
+      "git.pull_request.base_branch_sha": "bf6c156e8c1ec9cf43239162bca38cad22a3f4d2",
       "git.repository_url": "https://gitlab.com/repo/myrepo.git",
       "pr.number": "42"
     }