ci: run fmt-clippy-docs on beta

Author: Fishrock123

.github/workflows/ci.yaml

@@ -78,10 +78,10 @@ jobs:
     steps:
     - uses: actions/checkout@master
 
-    - name: nightly setup
+    - name: beta setup
       run: |
-        rustup toolchain install nightly
-        rustup default nightly
+        rustup toolchain install beta
+        rustup default beta
 
     - name: clippy
       run: cargo clippy --workspace --bins --examples --tests -- -D warnings