ci: add functionality to write new versions for lib

After determining the new version, this script enables writing the new version to the version file. This script does not check anything about the version, i.e. it sets the new version to whatever you tell it.

ghstack-source-id: 103a4347afc74790418de3c26486fff3c243d502
Pull Request resolved: csgoh#89

ci/version_writer.py

@@ -0,0 +1,38 @@
+#!/usr/bin/python3
+
+import os.path
+import subprocess
+import sys
+
+import version_retriever
+
+
+def update_version(new_version: str, version_file: str):
+    current_version = version_retriever.get_current_version()
+    path_to_version_file = get_absolute_path_to_version_file(version_file)
+    replace_current_with_new_version(current_version, new_version, path_to_version_file)
+
+
+def get_absolute_path_to_version_file(version_file: str):
+    git_repo_root = subprocess.Popen(['git', 'rev-parse', '--show-toplevel'], stdout=subprocess.PIPE) \
+        .communicate()[0] \
+        .rstrip() \
+        .decode('utf-8')
+    path_to_version_file = os.path.join(git_repo_root, version_file)
+    return path_to_version_file
+
+
+def replace_current_with_new_version(current_version, new_version, path_to_version_file):
+    with open(path_to_version_file, "r") as version_file:
+        file_data = version_file.read()
+    updated_file_data = file_data.replace(current_version, new_version)
+    with open(path_to_version_file, "w") as version_file:
+        version_file.write(updated_file_data)
+
+
+if __name__ == "__main__":
+    new_version = sys.argv[1]
+    version_file = "src/roadmapper/version.py"
+    update_version(new_version, version_file)
+
+    print(f"Version in `{version_file}` updated to `{new_version}`")