ci: add --force flag on toolchain install

Author: calebcartwright

ci/azure-install-rust.yml

@@ -4,7 +4,7 @@ steps:
       set -e
       curl https://sh.rustup.rs -sSf | sh -s -- -y --default-toolchain none
       export PATH=$PATH:$HOME/.cargo/bin
-      rustup toolchain install $RUSTUP_TOOLCHAIN
+      rustup toolchain install $RUSTUP_TOOLCHAIN --force
       rustup default $RUSTUP_TOOLCHAIN
       echo "##vso[task.setvariable variable=PATH;]$PATH:$HOME/.cargo/bin"
     env:
@@ -17,7 +17,7 @@ steps:
       curl -sSf -o rustup-init.exe https://win.rustup.rs
       rustup-init.exe -y --default-toolchain none
       set PATH=%PATH%;%USERPROFILE%\.cargo\bin
-      rustup toolchain install %RUSTUP_TOOLCHAIN%
+      rustup toolchain install %RUSTUP_TOOLCHAIN% --force
       rustup default %RUSTUP_TOOLCHAIN%
       echo "##vso[task.setvariable variable=PATH;]%PATH%;%USERPROFILE%\.cargo\bin"
     env: