Add OIDC tokens to gitlab-ci jobs (#39813)

* Add OIDC tokens to gitlab-ci jobs

This should allow us to start issuing just-in-time generated
credentials for CI jobs that need to modify binary mirrors. The "aud"
claim of the token describes what the token is allowed to do. The
claim is verified against a set of rules on the IAM role using signed
information from GitLab. See spack-infrastructure for the claim
verification logic.

---------

Co-authored-by: Scott Wittenburg <scott.wittenburg@kitware.com>

share/spack/gitlab/cloud_pipelines/configs/ci.yaml

@@ -32,6 +32,9 @@ ci:
         CI_JOB_SIZE: "default"
         CI_GPG_KEY_ROOT: /mnt/key
         # SPACK_VERBOSE_SCRIPT: "1"
+      id_tokens:
+        GITLAB_OIDC_TOKEN:
+          aud: "${OIDC_TOKEN_AUDIENCE}"
 
   - signing-job:
       image: { "name": "ghcr.io/spack/notary:latest", "entrypoint": [""] }
@@ -41,6 +44,9 @@ ci:
         - /sign.sh
         - aws s3 sync --exclude "*" --include "*spec.json.sig*" /tmp ${SPACK_REMOTE_MIRROR_OVERRIDE}/build_cache
         - aws s3 cp /tmp/public_keys ${SPACK_REMOTE_MIRROR_OVERRIDE}/build_cache/_pgp --recursive --exclude "*" --include "*.pub"
+      id_tokens:
+        GITLAB_OIDC_TOKEN:
+          aud: "${OIDC_TOKEN_AUDIENCE}"
 
   - copy-job:
       tags: ["service", "x86_64"]
@@ -68,6 +74,9 @@ ci:
         CI_JOB_SIZE: "medium"
         KUBERNETES_CPU_REQUEST: "4000m"
         KUBERNETES_MEMORY_REQUEST: "16G"
+      id_tokens:
+        GITLAB_OIDC_TOKEN:
+          aud: "${OIDC_TOKEN_AUDIENCE}"
 
   - reindex-job:
       tags: ["service", "x86_64"]
@@ -76,6 +85,9 @@ ci:
         CI_JOB_SIZE: "medium"
         KUBERNETES_CPU_REQUEST: "4000m"
         KUBERNETES_MEMORY_REQUEST: "16G"
+      id_tokens:
+        GITLAB_OIDC_TOKEN:
+          aud: "${OIDC_TOKEN_AUDIENCE}"
 
   - cleanup-job:
       tags: ["service"]
@@ -83,6 +95,9 @@ ci:
         CI_JOB_SIZE: "small"
         KUBERNETES_CPU_REQUEST: "500m"
         KUBERNETES_MEMORY_REQUEST: "500M"
+      id_tokens:
+        GITLAB_OIDC_TOKEN:
+          aud: "${OIDC_TOKEN_AUDIENCE}"
 
   - noop-job:
       tags: ["service"]