Git: Update current branch after some operations

... to refresh the branch view upstream status.

No need for a full model update here, only the current
branch is influenced.

Change-Id: I6bd17a841988b36221e5015a5858071d33a7b5e5
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/git/gitplugin.h

@@ -89,6 +89,7 @@ public:
     static QString invalidBranchAndRemoteNamePattern();
     void startCommit(CommitType commitType = SimpleCommit);
     void updateBranches(const QString &repository);
+    void updateCurrentBranch();
 
     QObject *remoteCommand(const QStringList &options, const QString &workingDirectory,
                            const QStringList &args) override;