Rename old toolchains on windows to speedup installation

Author: kiljacken

.github/workflows/ci.yaml

@@ -23,9 +23,13 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v1
 
-      - name: Cleanup Rust components (Windows)
+      # We need to disable the existing toolchain to avoid updating rust-docs
+      # which takes a long time. The fastest way to do this is to rename the
+      # existing folder, as deleting it takes about as much time as not doing
+      # anything and just updating rust-docs.
+      - name: Rename existing rust toolchain (Windows)
         if: matrix.os == 'windows-latest'
-        run: rustup component remove rust-docs
+        run: Rename-Item C:\Users\runneradmin\.rustup\toolchains\stable-x86_64-pc-windows-msvc C:\Users\runneradmin\.rustup\toolchains\stable-x86_64-pc-windows-msvc.old
 
       - name: Install Rust toolchain
         uses: actions-rs/toolchain@v1