Update golang version to v1.26.4 (#574)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

go.mod

@@ -1,6 +1,6 @@
 module github.com/newrelic/newrelic-prometheus-configurator
 
-go 1.26.2
+go 1.26.4
 
 require (
 	github.com/alecthomas/units v0.0.0-20240927000941-0f3dac36c52b