chore(api): maintain api version using poetry

Part-of: <https://dev.funkwhale.audio/funkwhale/funkwhale/-/merge_requests/2332>

changes/changelog.d/maintain-api-version-using-poetry.enhancement

@@ -0,0 +1 @@
+Maintain api version using poetry

docs/developer_documentation/workflows/release.md

@@ -55,10 +55,12 @@ Once we're ready to release a new version of the software, we can use the follow
    nano CHANGELOG # Add these lists to the CHANGELOG
    ```
 
-7. Update the `__version__` variable to the next release version
+7. Update the next release version
 
    ```sh
-   nano api/funkwhale_api/__init__.py
+   cd api
+   poetry version "$NEXT_RELEASE"
+   cd ..
    ```
 
 8. Commit all changes

scripts/set-api-build-metadata.sh

@@ -1,13 +1,22 @@
 #!/usr/bin/env bash
 
-set -eux
+# Given a commit hash, this script will update the version in api/pyproject.toml
+# The version must follow the pep440 specification https://peps.python.org/pep-0440/
 
-# given a commit hash, will append this to the version number stored
-# in api/funkwhale_api/__init__.py
+set -eu
 
-COMMIT=$1
-FILE="api/funkwhale_api/__init__.py"
+error() {
+  echo >&2 "error: $*"
+  exit 1
+}
 
-SUFFIX="\1+git.$COMMIT"
-EXPR=$(printf 's@__version__ = "(.*)"@__version__ = "%s"@' "$SUFFIX")
-sed -i -E "$EXPR" "$FILE"
+command -v poetry > /dev/null || error "poetry command not found!"
+
+COMMIT_SHA="$1"
+
+CURRENT_VERSION="$(poetry version --short)"
+CURRENT_VERSION="${CURRENT_VERSION%%.dev*}"
+
+VERSION_SUFFIX="dev+$COMMIT_SHA"
+
+poetry version "$CURRENT_VERSION.$VERSION_SUFFIX"