Updating to Go 1.19 (#230) (#231)

Author: bendbennett

.changes/unreleased/NOTES-20230303-105418.yaml

@@ -0,0 +1,6 @@
+kind: NOTES
+body: This Go module has been updated to Go 1.19 per the [Go support policy](https://golang.org/doc/devel/release.html#policy).
+  Any consumers building on earlier Go versions may experience errors.
+time: 2023-03-03T10:54:18.414865Z
+custom:
+  Issue: "231"

go.mod

@@ -1,6 +1,6 @@
 module github.com/hashicorp/terraform-plugin-docs
 
-go 1.18
+go 1.19
 
 require (
 	github.com/google/go-cmp v0.5.9