ci: Add a timeout for all jobs

Author: tgross35

library/compiler-builtins/.github/workflows/main.yaml

@@ -247,6 +247,7 @@ jobs:
   miri:
     name: Miri
     runs-on: ubuntu-24.04
+    timeout-minutes: 10
     steps:
     - uses: actions/checkout@v4
       with:
@@ -282,6 +283,7 @@ jobs:
   rustfmt:
     name: Rustfmt
     runs-on: ubuntu-24.04
+    timeout-minutes: 10
     steps:
     - uses: actions/checkout@v4
       with:
@@ -347,6 +349,7 @@ jobs:
       - rustfmt
       - test
     runs-on: ubuntu-24.04
+    timeout-minutes: 10
     # GitHub branch protection is exceedingly silly and treats "jobs skipped because a dependency
     # failed" as success. So we have to do some contortions to ensure the job fails if any of its
     # dependencies fails.