Add go mod version test

Add a script to make sure go.mod Go versions stay in sync.

Signed-off-by: SuperQ <superq@gmail.com>

.circleci/config.yml

@@ -76,6 +76,7 @@ jobs:
       - run: make style
       - run: make -C sigv4 style
       - run: make -C assets style
+      - run: make check-go-mod-version
       - when:
           condition: << parameters.use_gomod_cache >>
           steps:

Makefile

@@ -19,3 +19,8 @@ test:: deps check_license unused common-test lint
 .PHONY: generate-testdata
 generate-testdata:
 	@cd config && go run generate.go
+
+.PHONY: check-go-mod-version
+check-go-mod-version:
+	@echo ">> checking go.mod version matching"
+	@./scripts/check-go-mod-version.sh

scripts/check-go-mod-version.sh

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+
+readarray -t mod_files < <(find . -type f -name go.mod)
+
+echo "Checking files ${mod_files[@]}"
+
+matches=$(awk '$1 == "go" {print $2}' "${mod_files[@]}" | sort -u | wc -l)
+
+if [[ "${matches}" -ne 1 ]]; then
+  echo 'Not all go.mod files have matching go versions'
+  exit 1
+fi