bump version to v1.2

Author: humbletim

README.md

@@ -1,12 +1,12 @@
-# install-vulkan-sdk v1.1.2
+# install-vulkan-sdk v1.2
 
 This action automatically downloads and installs the Vulkan SDK development environment.
 
 ### Usage
 
 ```yaml
   -name: Install Vulkan SDK
-   uses: humbletim/install-vulkan-sdk@v1.1.2
+   uses: humbletim/install-vulkan-sdk@v1.2
    with:
      version: 1.4.309.0
      cache: true