yarn-plugin: do not attempt to convert backstage: versions in peerDependencies

Yarn does not support protocols other than npm and
workspace for peerDependencies - any other
protocols will produce an error and be converted
to '*' when running yarn. This change matches that
limitation in the beforeWorkspacePacking hook.

Signed-off-by: MT Lewis <mtlewis@users.noreply.github.com>

packages/yarn-plugin/src/handlers/beforeWorkspacePacking.ts

@@ -38,13 +38,9 @@ export const beforeWorkspacePacking = async (
   workspace: Workspace,
   rawManifest: any,
 ) => {
-  for (const dependencyType of [
-    'dependencies',
-    'devDependencies',
-    'peerDependencies',
-  ] as const) {
-    const backstageVersion = getCurrentBackstageVersion();
+  const backstageVersion = getCurrentBackstageVersion();
 
+  for (const dependencyType of ['dependencies', 'devDependencies'] as const) {
     const entries = Array.from(
       workspace.manifest.getForScope(dependencyType).values(),
     ).filter(descriptor => descriptor.range.startsWith(PROTOCOL));