Stop using deprecated set-output in GitHub Action workflows (#801)

.github/actions/ci-shared-setup/action.yml

@@ -30,7 +30,7 @@ runs:
       shell: bash
       run: |
         VERSION=$(cargo metadata --format-version=1 --locked | jq '.packages[] | select(.name == "wasmtime") | .version' -r)
-        echo "::set-output name=wasmtime_version::$VERSION"
+        echo "wasmtime_version=$VERSION" >> "$GITHUB_OUTPUT"
 
     - name: Install wasmtime-cli
       shell: bash

.github/workflows/check-fuzz.yml

@@ -1,6 +1,6 @@
 # Smoke test to build fuzz targets.
 # Deserves its own action given that it depends on nightly
-# and there's currently no way to define multiple toolchains through the 
+# and there's currently no way to define multiple toolchains through the
 # `rust-toolchain.toml` configuration file.
 name: Build Fuzz Targets
 on:
@@ -20,14 +20,14 @@ jobs:
         shell: bash
         run: |
           NIGHTLY_VERSION=$(cat pinned-nightly-version)
-          echo "::set-output name=nightly_version::$NIGHTLY_VERSION"
+          echo "nightly_version=$NIGHTLY_VERSION" >> "$GITHUB_OUTPUT"
 
       - name: Read cargo fuzz version
         id: cargo_fuzz_version
         shell: bash
         run: |
           CARGO_FUZZ_VERSION=$(cat pinned-cargo-fuzz-version)
-          echo "::set-output name=cargo_fuzz_version::$CARGO_FUZZ_VERSION"
+          echo "cargo_fuzz_version=$CARGO_FUZZ_VERSION" >> "$GITHUB_OUTPUT"
 
       - name: Install nightly
         run: |