Do not ivalidate the cache entirely on lock file change (#744)

* Do not ivalidate the cache entirely on yarn3 lock file change

* Use cache prefix if all sub-projects are yarn managed

* Rename functions & add e2e tests

__tests__/prepare-yarn-subprojects.sh

@@ -0,0 +1,59 @@
+#!/bin/sh -e
+export YARN_ENABLE_IMMUTABLE_INSTALLS=false
+rm package.json
+rm package-lock.json
+echo "create yarn2 project in the sub2"
+mkdir sub2
+cd sub2
+cat <<EOT >package.json
+{
+  "name": "subproject",
+  "dependencies": {
+    "random": "^3.0.6",
+    "uuid": "^9.0.0"
+  }
+}
+EOT
+yarn set version 2.4.3
+yarn install
+
+echo "create yarn3 project in the sub3"
+cd ..
+mkdir sub3
+cd sub3
+cat <<EOT >package.json
+{
+  "name": "subproject",
+  "dependencies": {
+    "random": "^3.0.6",
+    "uuid": "^9.0.0"
+  }
+}
+EOT
+yarn set version 3.5.1
+yarn install
+if [ x$1 = 'xglobal' ];then
+  echo enableGlobalCache
+  echo 'enableGlobalCache: true' >> .yarnrc.yml
+fi
+
+cd ..
+if [ x$1 != 'xkeepcache' -a x$2 != 'xkeepcache' ]; then
+  rm -rf sub2/.yarn/cache
+  rm -rf sub3/.yarn/cache
+fi
+
+if [ x$1 = 'xyarn1' ];then
+  echo "create yarn1 project in the root"
+  cat <<EOT >package.json
+{
+  "name": "subproject",
+  "dependencies": {
+    "random": "^3.0.6",
+    "uuid": "^9.0.0"
+  }
+}
+EOT
+  yarn set version 1.22.19
+  yarn install
+fi