build: update .go-version to unblock netlify build (open-policy-agent…

…#6605)

With .go-version containing 1.22, netlify fails to pick up the golang binary:

    9:32:09 AM: Installing Go version 1.22 (requested 1.22)
    9:32:09 AM: Failed to install Go version "1.22"
    9:32:12 AM: Continue with existing version "1.19.13"

and the build breaks with 1.19.x.

Setting .go-version to 1.22.0 (with .0 at the end) matches the versioning
scheme on https://go.dev/dl/, and it seems to succeed picking up the right
go version for the website build:

    9:33:35 AM: Installing Go version 1.22.0 (requested 1.22.0)
    9:33:37 AM: go version go1.22.0 linux/amd64

Signed-off-by: Stephan Renatus <stephan@styra.com>
Signed-off-by: Thomas Sidebottom <thomas.sidebottom@va.gov>

.go-version

@@ -1 +1 @@
-1.22
+1.22.0