Test with Go 1.14.1 only. (#4785)

Now that we've deployed Go 1.14.1 in prod, we can remove 1.13.2 from our
test matrix.

.travis.yml

@@ -3,7 +3,6 @@ dist: xenial
 os: linux
 
 go:
-  - "1.13.2"
   - "1.14.1"
 
 go_import_path: github.com/letsencrypt/boulder

docker-compose.yml

@@ -2,7 +2,7 @@ version: '3'
 services:
     boulder:
         # To minimize fetching this should be the same version used below
-        image: letsencrypt/boulder-tools-go${TRAVIS_GO_VERSION:-1.13.2}:2020-04-08
+        image: letsencrypt/boulder-tools-go${TRAVIS_GO_VERSION:-1.14.1}:2020-04-08
         environment:
             FAKE_DNS: 10.77.77.77
             PKCS11_PROXY_SOCKET: tcp://boulder-hsm:5657
@@ -65,7 +65,7 @@ services:
             hard: -1
     bhsm:
         # To minimize fetching this should be the same version used above
-        image: letsencrypt/boulder-tools-go${TRAVIS_GO_VERSION:-1.13.2}:2020-04-08
+        image: letsencrypt/boulder-tools-go${TRAVIS_GO_VERSION:-1.14.1}:2020-04-08
         environment:
             PKCS11_DAEMON_SOCKET: tcp://0.0.0.0:5657
         command: /usr/local/bin/pkcs11-daemon /usr/lib/softhsm/libsofthsm2.so
@@ -92,7 +92,7 @@ services:
         logging:
             driver: none
     netaccess:
-        image: letsencrypt/boulder-tools-go${TRAVIS_GO_VERSION:-1.13.2}:2020-04-08
+        image: letsencrypt/boulder-tools-go${TRAVIS_GO_VERSION:-1.14.1}:2020-04-08
         environment:
             GO111MODULE: "on"
             GOFLAGS: "-mod=vendor"

test/boulder-tools/tag_and_upload.sh

@@ -4,7 +4,7 @@ cd $(dirname $0)
 
 DATESTAMP=$(date +%Y-%m-%d)
 BASE_TAG_NAME="letsencrypt/boulder-tools"
-GO_VERSIONS=( "1.13.2" "1.14.1" )
+GO_VERSIONS=( "1.14.1" )
 
 # Build a tagged image for each GO_VERSION
 for GO_VERSION in "${GO_VERSIONS[@]}"