Update bootstrap buildcache to v0.3 (#32262)

This release allow to bootstrap patchelf from binaries.

etc/spack/defaults/bootstrap.yaml

@@ -9,6 +9,8 @@ bootstrap:
   # may not be able to bootstrap all the software that Spack needs,
   # depending on its type.
   sources:
+  - name: 'github-actions-v0.3'
+    metadata: $spack/share/spack/bootstrap/github-actions-v0.3
   - name: 'github-actions-v0.2'
     metadata: $spack/share/spack/bootstrap/github-actions-v0.2
   - name: 'github-actions-v0.1'
@@ -18,5 +20,5 @@ bootstrap:
   trusted:
     # By default we trust bootstrapping from sources and from binaries
     # produced on Github via the workflow
-    github-actions-v0.2: true
+    github-actions-v0.3: true
     spack-install: true