Fix PyPI package publishing in CI (#5669)

* Fix PyPI package publishing in CI

* Update .circleci/workflows.yml

Co-authored-by: Mike Williams <102263964+mikewilli@users.noreply.github.com>

---------

Co-authored-by: Mike Williams <102263964+mikewilli@users.noreply.github.com>

.circleci/workflows.yml

@@ -1046,6 +1046,16 @@ jobs:
     docker: *docker
     steps:
       - checkout
+      - run:
+          name: Check for package version change in last commit before proceeding.
+          command: |
+            if git diff main HEAD~1 pyproject.toml | grep 'version'
+              then
+                echo "Found changes to package version dir, proceeding with deployment."
+              else
+                echo "No changes in package version. Skipping bigquery-etl deployment."
+                circleci-agent step halt
+            fi
       - run:
           name: Install deployment tools
           command: |
@@ -1211,8 +1221,6 @@ workflows:
     jobs:
       - deploy-to-pypi:
           filters:
-            tags:
-              only: /[0-9]{4}.[0-9]{1,2}.[0-9]+/  # Calver: YYYY.M.MINOR
             branches:
-              # Ignore all branches; this workflow should only run for tags.
-              ignore: /.*/
+              only:
+                - main

README.md

@@ -47,3 +47,8 @@ cp .vscode/launch.json.default .vscode/launch.json
 ```
 
 And you should now be set up to start working in the repo! The easiest way to do this is for many tasks is to use [`bqetl`](https://mozilla.github.io/bigquery-etl/bqetl/). You may also want to read up on [common workflows](https://mozilla.github.io/bigquery-etl/cookbooks/common_workflows/).
+
+
+## Releasing a new version of `bqetl`
+
+To push a new version of `bqetl` to [PyPI](https://pypi.org/project/mozilla-bigquery-etl/), update the `version` in [`pyproject.toml`](pyproject.toml). The version numbers follow the [CalVer](https://calver.org/) scheme, with the _Micro_ version numbers starting at 1. For example, for the first package version getting published in March 2024, the version would be `2024.3.1`.

pyproject.toml

@@ -10,7 +10,8 @@ authors = [
 description = "Tooling for building derived datasets in BigQuery"
 readme = "README.md"
 requires-python = ">=3.11"
-dynamic = ["dependencies", "version"]
+dynamic = ["dependencies"]
+version = "2024.5.1"
 
 [project.urls]
 Homepage = "https://github.com/mozilla/bigquery-etl"