Merge pull request #17902 from vector-im/gsouquet/ci-pure-lockfile

Do not generate a lockfile when running in CI

scripts/fetch-develop.deps.sh

@@ -76,7 +76,7 @@ dodep matrix-org matrix-js-sdk
 
 pushd matrix-js-sdk
 yarn link
-yarn install
+yarn install --pure-lockfile
 popd
 
 yarn link matrix-js-sdk
@@ -90,7 +90,7 @@ dodep matrix-org matrix-react-sdk
 pushd matrix-react-sdk
 yarn link
 yarn link matrix-js-sdk
-yarn install
+yarn install --pure-lockfile
 yarn reskindex
 popd