The build is failing due to a missing module during the yarn build
pypi build:
```
17:33:59 + yarn build
17:33:59 yarn run v1.22.5
17:33:59 $ yarn build-so && yarn build-wasm
17:33:59 $ yarn generate && cd query_language && python3 build.py
17:33:59 $ cd query_language && tree-sitter generate --no-bindings && echo 'Generated parser files '
17:34:00 Generated parser files
17:34:00 Traceback (most recent call last):
17:34:00 File "build.py", line 1, in <module>
17:34:00 from tree_sitter import Language
17:34:00 ModuleNotFoundError: No module named 'tree_sitter'
17:34:00 error Command failed with exit code 1.
```
Debian build, 2 issues:
```
16:42:50 running ts_build_export
16:42:50 running ts_install
16:42:50 sh: 1: yarn: not found
16:42:50 running ts_build
16:42:50 running ts_build_so
16:42:50 sh: 1: yarn: not found
16:42:50 running ts_build_wasm
16:42:50 sh: 1: yarn: not found
16:42:50 static files generated. copying them to package dir
16:42:50 cp: cannot stat 'query_language/swh_ql.so': No such file or directory
16:42:50 cp: cannot stat 'query_language/swh_ql.wasm': No such file or directory
```
```
16:42:51 ============================= test session starts ==============================
16:42:51 platform linux -- Python 3.9.2, pytest-6.0.2, py-1.10.0, pluggy-0.13.0
16:42:51 rootdir: /<<PKGBUILDDIR>>, configfile: pytest.ini
16:42:51 plugins: swh.journal-0.8.0, swh.core-0.14.4, mock-1.10.4, hypothesis-5.43.3
16:42:51 collected 131 items / 2 errors / 129 selected
16:42:51 Hint: make sure your test modules/packages have valid Python names.
16:42:51 Traceback:
16:42:51 /usr/lib/python3.9/importlib/__init__.py:127: in import_module
16:42:51 return _bootstrap._gcd_import(name[level:], package, level)
16:42:51 swh/search/tests/test_translator.py:3: in <module>
16:42:51 from swh.search.translator import Translator
16:42:51 swh/search/translator.py:4: in <module>
16:42:51 from tree_sitter import Language, Parser
16:42:51 E ModuleNotFoundError: No module named 'tree_sitter'
16:42:51 =============================== warnings summary ===============================
```