Bump to go 1.16, remove master from tests

Author: maddyblue

Diff for: .travis.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 
-set -eu
+set -eux
 
 client_configure() {
 	sudo chmod 600 $PQSSLCERTTEST_PATH/postgresql.key

Diff for: .travis.yml

@@ -1,9 +1,8 @@
 language: go
 
 go:
-  - 1.14.x
   - 1.15.x
-  - master
+  - 1.16.x
 
 sudo: true