Add release matrix json for consumption by PyTorch website (#1848)

* Add creation of release_matrix.json to gen_quick_start_module.py

The PyTorch website needs access to the "release matrix" in the same way it can access published_version.json to generate the config needed for the "Start Locally" page.

* Add all updated files to commit message in update-quick-start-module.yml

* Add comment to new function to save json file in  gen_quick_start_module.py

---------

Co-authored-by: Andrey Talman <atalman@fb.com>

Author: marco-s

.github/workflows/update-quick-start-module.yml

@@ -105,8 +105,8 @@ jobs:
         uses: peter-evans/create-pull-request@v3
         with:
           token: ${{ secrets.PYTORCHBOT_TOKEN }}
-          commit-message: Modify published_versions.json file
-          title: '[Getting Started Page] Modify published_versions.json file'
+          commit-message: Modify published_versions.json, release_matrix.json and quick-start-module.js
+          title: '[Getting Started Page] Modify published_versions.json, release_matrix.json and quick-start-module.js'
           body: >
             This PR is auto-generated. It updates Getting Started page
           labels: automated pr

scripts/gen_quick_start_module.py

@@ -83,6 +83,12 @@ def write_published_versions(versions):
     with open(BASE_DIR / "published_versions.json", "w") as outfile:
         json.dump(versions, outfile, indent=2)
 
+# Create release matrix for PyTorch website.
+# It's utilized to populate config data for 
+# the "Start Locally" installation options table.
+def write_release_matrix(matrix):
+    with open(BASE_DIR / "release_matrix.json", "w") as outfile:
+        json.dump(matrix, outfile, indent=2)
 
 def read_matrix_for_os(osys: OperatingSystem, channel: str):
     jsonfile = load_json_from_basedir(f"{osys.value}_{channel}_matrix.json")
@@ -242,6 +248,8 @@ def main():
             for osys in OperatingSystem:
                 release_matrix[val][osys.value] = read_matrix_for_os(osys, val)
 
+        write_release_matrix(release_matrix)
+
         extract_arch_ver_map(release_matrix)
         for val in ("nightly", "release"):
             update_versions(versions, release_matrix[val], val)