Time out workflows after 45 minutes

GitHub's default timeout is 6 hours. Recently some of my GitHub Actions
jobs have started randomly stalling for that long, which is inconvenient
because it ties up a chunk of my runner quota. It apepars to be very
rare for a job to recover after stalling. It's better to time out
quicker and retry on a different runner.

.github/workflows/ci.yml

@@ -19,6 +19,7 @@ jobs:
       fail-fast: false
       matrix:
         rust: [nightly, beta, stable, 1.56.0]
+    timeout-minutes: 45
     steps:
       - uses: actions/checkout@v3
       - uses: dtolnay/rust-toolchain@master
@@ -33,6 +34,7 @@ jobs:
   examples:
     name: Examples
     runs-on: ubuntu-latest
+    timeout-minutes: 45
     steps:
       - uses: actions/checkout@v3
       - uses: dtolnay/rust-toolchain@nightly
@@ -47,6 +49,7 @@ jobs:
     name: Clippy
     runs-on: ubuntu-latest
     if: github.event_name != 'pull_request'
+    timeout-minutes: 45
     steps:
       - uses: actions/checkout@v3
       - uses: dtolnay/rust-toolchain@clippy
@@ -56,6 +59,7 @@ jobs:
     name: Outdated
     runs-on: ubuntu-latest
     if: github.event_name != 'pull_request'
+    timeout-minutes: 45
     steps:
       - uses: actions/checkout@v3
       - uses: dtolnay/install@cargo-outdated