Reduce warnings on CI from GitHub Actions (#5083)

* Upgrade our github actions to "node16"

Each github actions run has a lot of warnings about using node12 so this
upgrades our repository to using node16. I'm hoping no other changes are
needed and I suspect other actions we're using are on node12 and will
need further updates, but this should help pin down what's remaining.

* Update `actions/checkout` workflow to `v3`

* Update to `actions/cache@v3`

* Update to `actions/upload-artifact@v3`

* Drop usage of `actions-rs/toolchain`

* Update to `actions/setup-python@v4`

* Update mdbook version

.github/workflows/performance.yml

@@ -77,11 +77,7 @@ jobs:
           submodules: true
           path: wasmtime_commit
 
-      - name: Get latest rust toolchain
-        uses: actions-rs/toolchain@v1
-        with:
-          toolchain: nightly
-          override: true
+      - run: rustup update nightly && rustup default nightly
 
       - name: Build patch from bytecodealliance/wasmtime (pushed and triggering on this perf repo)
         working-directory: ./wasmtime_commit
@@ -120,7 +116,7 @@ jobs:
           ./target/release/sightglass-cli summarize --input-format csv  --output-format csv -f /tmp/results.csv > /tmp/results_summarized.csv
 
       - name: Setup Python
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v4
         with:
           python-version: '3.9'