bump version to v2.9.1

Author: kost

Makefile

@@ -1,6 +1,6 @@
 OUTPUT_DIR = ./builds
 GIT_COMMIT = `git rev-parse HEAD | cut -c1-7`
-VERSION = 2.9.0
+VERSION = 2.9.1
 BUILD_OPTIONS = -ldflags "-X main.Version=$(VERSION) -X main.CommitID=$(GIT_COMMIT)"
 STATIC_OPTIONS = -ldflags "-extldflags='-static' -X main.Version=$(VERSION) -X main.CommitID=$(GIT_COMMIT)"
 WEBPACK_MODE = production