Perform some CI/dependency maintenance

* Update dependencies along their major version track
* Remove 1.90.0 pinning in CI as the upstream Rust issue is fixed
* Actually test MSRV in CI, and accurately bump it to 1.88 since the
  previously listed 1.87 did not work.
* Downgrade the MSRV of the `wit-bindgen` crate to being more
  conservative, at this time 1.85 (same as wasm-tools with N-10).

Author: alexcrichton

.github/workflows/main.yml

@@ -89,9 +89,8 @@ jobs:
     - uses: actions/checkout@v4
       with:
         submodules: true
-    # FIXME(rust-lang/rust#148347) current rust (1.91) is broken
     - name: Install Rust
-      run: rustup update 1.90.0 --no-self-update && rustup default 1.90.0
+      run: rustup update stable --no-self-update && rustup default stable
     - run: rustup target add wasm32-wasip1 wasm32-wasip2
 
     - run: rustup target add wasm32-unknown-unknown
@@ -244,6 +243,18 @@ jobs:
     - name: Format source code
       run: cargo fmt -- --check
 
+  msrv:
+    name: Verify MSRV
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    # Verify MSRV for the whole workspace
+    - run: rustup update 1.88.0 && rustup default 1.88.0
+    - run: cargo check
+    # Verify the tighter MSRV of the `wit-bindgen` crate.
+    - run: rustup update 1.85.0 && rustup default 1.85.0
+    - run: cargo check -p wit-bindgen --all-features
+
   verify-publish:
     if: github.repository_owner == 'bytecodealliance'
     runs-on: ubuntu-latest
@@ -269,6 +280,7 @@ jobs:
       - build
       - verify-publish
       - check
+      - msrv
       # - async
     if: always()