Merge pull request #272 from Yaskawa-Global/ci_support_mrm_prereleases

ci: support downloading `micro_ros_motoplus` prereleases

.github/workflows/ci_msbuild.yaml

@@ -58,11 +58,7 @@ jobs:
       matrix:
         controller: [dx200, yrc1000, yrc1000u]
         # officially matrix doesn't support non-scalar values, but it does
-        # seem to work, so let's use it. We specify M+ uROS release distributions
-        # like this as it provides a (very) compact way to specify specific
-        # upstream releases. As not all controllers have all releases of all
-        # supported ROS 2 versions, this is less verbose than having to 'include'
-        # or 'exclude' certain entries from a regular full matrix spec (with lists).
+        # seem to work, so let's use it.
         uros: [
           { release: 20221102, codename: foxy     },
           { release: 20221102, codename: galactic },
@@ -99,14 +95,15 @@ jobs:
       shell: bash
       env:
         GITHUB_TOKEN: ${{ steps.gen_token.outputs.token }}
+        RELEASE_TYPE: ${{ (matrix.uros.prerelease && 'prerelease') || 'release' }}
       run: |
         gh \
           release \
             --repo="yaskawa-global/micro_ros_motoplus" \
           download \
             --pattern="micro_ros_motoplus*.zip" \
             --output="micro_ros_motoplus.zip" \
-            release-${{ matrix.uros.codename }}-${{ matrix.controller }}-${{ matrix.uros.release }}
+            ${{ env.RELEASE_TYPE }}-${{ matrix.uros.codename }}-${{ matrix.controller }}-${{ matrix.uros.release }}
 
     - name: Setup MotoROS2 build dir
       shell: bash