Bump version to 0.2.1

Example/Podfile.lock

 PODS:
-  - GMCache (0.1.2):
+  - GMCache (0.2.0):
     - TMCache (= 2.1.0)
   - TMCache (2.1.0)
 
@@ -11,7 +11,7 @@ EXTERNAL SOURCES:
     :path: ../
 
 SPEC CHECKSUMS:
-  GMCache: ab03b092a8d0692393af66c11c5e1cd82fcb6ead
+  GMCache: b7d48432ee2469eb0c6c86c720a1958bd373187e
   TMCache: 95ebcc9b3c7e90fb5fd8fc3036cba3aa781c9bed
 
 PODFILE CHECKSUM: 8d482f956ed77b240df3be8144ac3958c903d882

GMCache.podspec

@@ -8,7 +8,7 @@
 
 Pod::Spec.new do |s|
     s.name             = "GMCache"
-    s.version          = "0.2.0"
+    s.version          = "0.2.1"
     s.summary          = "缓存"
     s.homepage         = "http://git.wanmeizhensuo.com/gengmeiios/GMCache"
     s.license          = 'MIT'