Bump to go 1.18 semantics

go.mod

@@ -1,6 +1,6 @@
 module go.pinniped.dev
 
-go 1.17
+go 1.18
 
 require (
 	github.com/MakeNowJust/heredoc/v2 v2.0.1

hack/module.sh

@@ -9,7 +9,7 @@ ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
 
 function tidy_cmd() {
   local version="$(cat "${ROOT}/go.mod" | grep '^go ' | cut -f 2 -d ' ')"
-  echo "go mod tidy -v -go=${version} -compat=1.17"
+  echo "go mod tidy -v -go=${version} -compat=${version}"
 }
 
 function lint_cmd() {