@uppy/companion: fix deploy Yarn version (#3327)

* @uppy/companion: fix deploy

When running from the Dockerfile, Corepack cannot pick up the
information from the parent package.json and tries to run with an
older version of Yarn.

* Update update-yarn.sh

bin/update-yarn.sh

@@ -1,4 +1,10 @@
 #!/usr/bin/env bash
+
+# This script is meant to be run on a dev's machine to update the version on
+# Yarn used by the monorepo. Its goal is to make sure that every mention of Yarn
+# version is updated, and it re-installs the plugins to make sure those are
+# up-to-date as well.
+
 set -o pipefail
 set -o errexit
 set -o nounset
@@ -21,7 +27,9 @@ PLUGINS=$(awk '{ if ($1 == "spec:") print $2 }' .yarnrc.yml)
 echo "$PLUGINS" | xargs -n1 -t corepack yarn plugin remove
 
 cp package.json .yarn/cache/tmp.package.json
-sed "s#yarn\": \"$CURRENT_VERSION\"#yarn\": \"$LAST_VERSION\"#;s#\"yarn@$CURRENT_VERSION\"#\"yarn@$LAST_VERSION\"#" .yarn/cache/tmp.package.json > package.json
+sed "s#\"yarn\": \"$CURRENT_VERSION\"#\"yarn\": \"$LAST_VERSION\"#;s#\"yarn@$CURRENT_VERSION\"#\"yarn@$LAST_VERSION\"#" .yarn/cache/tmp.package.json > package.json
+cp packages/@uppy/companion/package.json .yarn/cache/tmp.package.json
+sed "s#\"yarn\": \"$CURRENT_VERSION\"#\"yarn\": \"$LAST_VERSION\"#;s#\"yarn@$CURRENT_VERSION\"#\"yarn@$LAST_VERSION\"#" .yarn/cache/tmp.package.json > packages/@uppy/companion/package.json
 rm .yarn/cache/tmp.package.json
 
 echo "$PLUGINS" | xargs -n1 -t corepack yarn plugin import

packages/@uppy/companion/package.json

@@ -112,7 +112,9 @@
     "test": "bash -c 'source env.test.sh && ../../../node_modules/jest/bin/jest.js'",
     "test:watch": "yarn test -- --watch"
   },
+  "packageManager": "yarn@3.1.0",
   "engines": {
-    "node": ">=10.20.1"
+    "node": ">=10.20.1",
+    "yarn": "3.1.0"
   }
 }