docs: Update Go version references to 1.19

Signed-off-by: Anoop C S <[email protected]>

Author: anoopcs9

docs/CONTRIBUTING.md

@@ -17,7 +17,7 @@ resources.
 Development effort takes place using Linux environment and requires at
 minimum:
 
-1. [Go 1.18](https://golang.org/dl/) installed
+1. [Go 1.19](https://golang.org/dl/) installed
 2. [GitHub](https://github.com/) account
 3. Development tools: git, make, and podman or docker
 4. Testing: [minikube](https://minikube.sigs.k8s.io)

docs/developers-notes.md

@@ -4,7 +4,7 @@
 ## Build from source
 
 The top-level [Makefile](../Makefile) is the entry point for various build
-commands. The minimal required Go version is 1.18. A developer can verify the
+commands. The minimal required Go version is 1.19. A developer can verify the
 build environment by running:
 
 ```bash