feat(use) - support "stable" as bvm use argument (#95)

teambit.bvm/commands/use/use.ts

@@ -16,6 +16,8 @@ export class UseCmd implements CommandModule {
     })
     .example('$0 use', 'show currently used version of bit')
     .example('$0 use 1.7.5', 'switch to version 1.7.5 of bit')
+    .example('$0 use stable', 'switch to latest installed stable version')
+    .example('$0 use latest', 'switch to latest installed version')
     return yargs;
   }
   async handler(args) {

teambit.bvm/link/link.ts

@@ -79,6 +79,13 @@ export async function linkOne(linkName: string, version: string | undefined, opt
     const localLatest = (await listLocal()).latest();
     concreteVersion = localLatest.version;
   }
+  if (concreteVersion === 'stable'){
+    const localStable = (await listLocal()).stable();
+    if (!localStable){
+      throw new BvmError(`no stable version found installed`);
+    }
+    concreteVersion = localStable.version;
+  }
   const {versionDir, exists} = config.getSpecificVersionDir(concreteVersion, true);
   if (!exists){
     throw new BvmError(`version ${concreteVersion} is not installed`);

teambit.bvm/list/version-list/version-list.ts

@@ -10,6 +10,11 @@ export class VersionList {
     return sorted.entries[0];
   }
 
+  stable(): Version | undefined {
+    const sorted = this.sortBySemver('desc');
+    return sorted.entries.find(version => version.releaseType === 'stable');
+  }
+
   find(version: string): Version | undefined {
     return this.entries.find(entry => entry.version === version);
   }