Remove pinned Rust version again

.github/workflows/ci.yaml

@@ -53,19 +53,11 @@ jobs:
     - name: Install Rust toolchain
       uses: actions-rs/toolchain@v1
       with:
-        toolchain: 1.49.0   # FIXME: CI is failing on 1.50
+        toolchain: stable
         profile: minimal
         override: true
         components: rustfmt, rust-src
 
-    - name: Install rustfmt
-      uses: actions-rs/toolchain@v1
-      with:
-        toolchain: stable
-        profile: minimal
-        override: false
-        components: rustfmt
-
     - name: Cache cargo directories
       uses: actions/cache@v2
       with: