.circleci: try pinning golang.org/x/net with a replace directive

Doing `go get` didn't fix the issue

.circleci/config.yml

@@ -253,9 +253,6 @@ jobs:
             go get github.com/Shopify/sarama@v1.22.0
             # Temporary enforcing gorm to v1.22.4 to avoid the problems of v1.22.5
             go get -v gorm.io/gorm@v1.22.4
-            # Pin last version of golang.org/x/net, later version require
-            # os.ErrDeadlineExceeded which is only available for Go >=1.15
-            go get golang.org/x/net@d418f374d
 
       - run:
           name: Wait for MySQL
@@ -307,6 +304,9 @@ jobs:
             PACKAGE_NAMES=$(go list ./contrib/... | grep -v -e grpc.v12 -e google.golang.org/api | circleci tests split --split-by=timings --timings-type=classname)
             export DD_APPSEC_ENABLED=$(test "<< parameters.build_tags >>" = appsec && echo -n true)
             export INTEGRATION=true
+            # Pin last version of golang.org/x/net, later version require
+            # os.ErrDeadlineExceeded which is only available for Go >=1.15
+            go mod edit -replace=golang.org/x/net=golang.org/x/net@d418f374d
             gotestsum --junitfile ${TEST_RESULTS}/gotestsum-report.xml -- $PACKAGE_NAMES -v -race -coverprofile=coverage.txt -covermode=atomic -tags "<< parameters.build_tags >>"
 
       - store_artifacts: # upload test summary for display in Artifacts