disable rustup self update for windows

This change fixes the Github Actions runs on Windows,
using one of the workarounds described in
rust-lang/rustup#3709

Author: goatshriek

.github/workflows/windows.yml

@@ -24,6 +24,7 @@ jobs:
         run: git submodule update --init
       - name: Update Rust
         run: |
+          rustup set auto-self-update disable
           rustup update ${{ matrix.toolchain }}
           rustup default ${{ matrix.toolchain }}
           rustup component add rustfmt
@@ -52,6 +53,7 @@ jobs:
         run: git submodule update --init
       - name: Update Rust
         run: |
+          rustup set auto-self-update disable
           rustup update ${{ matrix.toolchain }}
           rustup default ${{ matrix.toolchain }}
           rustup component add rustfmt