Add info for new version

tools/README.md

@@ -1,5 +1,56 @@
 # README
 
+## Add a new version:
+
+1. Update `.env` to the new version
+
+1. Add a line to `VAR:url_postfixes` in the file
+   `00_fetch_ud_clarin-dspace_metadata.py`, like:
+   > "2.16": "11234/1-5901",  # 319 treebanks, 179 languages, released May 15, 2025.
+
+   and execute:
+   ```
+   ./00_fetch_ud_clarin-dspace_metadata.py
+   ```
+
+1. Add a line to `ARRAY:VER_MAPPINGS` in the file
+   `00`, like:
+   > VER_MAPPING["2.16"]="bc0cc9b94112253e3ea1e00b2dbe3a46c5f53fe3"
+
+   and execute:
+   ```
+   ./00_fetch_ud_codes_and_flags.sh -o
+   ./01_fetch_ud_repos.sh
+   ```
+
+1. Execute:
+   ```
+   cd UD_repos/                   # change into the directory where all UD data resides
+   git checkout -b 2.16           # start a new branch for the new version
+   . .UD_submodules_add.commands  # update the submodules
+   git add -u                     # (or check if new directories have been added...)
+   git commit -m"Bump to 2.16"    # commit
+   cd ..
+   ```
+
+1. Execute:
+   ```
+   ./02_traverse_ud_repos.py -o
+   ./03_fill_universal_dependencies_tamplate.py -o
+
+   git log   # find the HASH *before* the "WIP" and
+   git reset HASH
+   git add README-2.16 metadata-2.16.json universal_dependencies-2.16
+   git commit -m"Add README-2.16 metadata-2.16.json universal_dependencies-2.16"
+   git checkout -b 2.16
+   cp README-2.16 ../README.md ; cp metadata-2.16.json ../metadata.json ; cp universal_dependencies-2.16 ../universal_dependencies.py
+   git commit -m"Sync README.md metadata.json universal_dependencies.py" ../README.md ../metadata.json ../universal_dependencies.py
+   git checkout main
+   git commit -m"WIP: 2.16 - Sync README.md metadata.json universal_dependencies.py" ../README.md ../metadata.json ../universal_dependencies.py
+   git push origin 2.14
+   git push -f origin main
+   ```
+
 ## 00 (./etc/)
 ### `00_fetch_ud_clarin-dspace_metadata.py`
 Download `./etc/citation-VER` and `./etc/description-VER` UD metadata files for