ci: unbreak workflow YAML (colon in unquoted step name)

The style pass rewrote an em dash as a colon inside an unquoted name:
scalar, which YAML reads as a nested mapping. Comma instead; file
re-validated with a YAML parse.

.github/workflows/ci.yml

@@ -191,7 +191,7 @@ jobs:
           sudo apt-get update -qq
           sudo apt-get install -y -qq gcc-arm-linux-gnueabihf qemu-system-arm \
             cpio bc bison flex libssl-dev ccache
-      - name: provision `python` (SDK quirk: build calls bare python)
+      - name: provision `python` (SDK quirk, the build calls bare python)
         run: |
           mkdir -p "$RUNNER_TEMP/bin"
           ln -sf "$(command -v python3)" "$RUNNER_TEMP/bin/python"