git: force a new branch to be created

Signed-off-by: Sean Cross <[email protected]>

.github/workflows/nightly.yml

@@ -44,7 +44,7 @@ jobs:
       - name: Determine nightly hash
         shell: bash
         run: |
-          export rustrevshort="$(rustc --version | awk -F '[\( ]+' '{print $3}')"
+          export rustrevshort="$(rustc --version | awk -F '[( ]+' '{print $3}')"
           echo "rustrevshort=$rustrevshort" >> $GITHUB_OUTPUT
           export rustrev="$(curl --silent \
             -H "Accept: application/vnd.github+json" \
@@ -78,7 +78,7 @@ jobs:
           && git remote add origin https://github.com/rust-lang/rust \
           && git config --local gc.auto 0 \
           && git -c protocol.version=2 fetch --no-tags --prune --progress --recurse-submodules --depth=1 origin $rustrev \
-          && git checkout $rustrev \
+          && git checkout -B master $rustrev \
           && git submodule sync --recursive \
           && git -c protocol.version=2 submodule update --init --force --depth=1 --recursive \
           && ls \