Add Go 1.12 to Travis CI

Also update to the latest version of Makefile.common.

Signed-off-by: Simon Pasquier <spasquie@redhat.com>

.travis.yml

@@ -1,4 +1,3 @@
-sudo: false
 language: go
 
 go:
@@ -7,7 +6,10 @@ go:
   - 1.9.x
   - 1.10.x
   - 1.11.x
+  - 1.12.x
 
 script:
-  - make check_license style unused test-short
+  - make check_license unused test-short
   - if [[ ! $TRAVIS_GO_VERSION =~ ^1\.(7|8|9)\.[x0-9]+$ ]]; then make staticcheck; fi
+  # style is only checked against the latest supported Go version.
+  - if [[ $TRAVIS_GO_VERSION =~ ^1\.(12)\. ]]; then make style; fi

Makefile.common

@@ -70,7 +70,7 @@ else
 	GO_BUILD_PLATFORM ?= $(GOHOSTOS)-$(GOHOSTARCH)
 endif
 
-PROMU_VERSION ?= 0.2.0
+PROMU_VERSION ?= 0.3.0
 PROMU_URL     := https://github.com/prometheus/promu/releases/download/v$(PROMU_VERSION)/promu-$(PROMU_VERSION).$(GO_BUILD_PLATFORM).tar.gz
 STATICCHECK_VERSION ?= 2019.1
 STATICCHECK_URL     := https://github.com/dominikh/go-tools/releases/download/$(STATICCHECK_VERSION)/staticcheck_$(GOHOSTOS)_$(GOHOSTARCH)
@@ -87,14 +87,14 @@ ifeq ($(GOHOSTARCH),amd64)
         endif
 endif
 
-.PHONY: all
-all: precheck style staticcheck unused build test
-
 # This rule is used to forward a target like "build" to "common-build".  This
 # allows a new "build" target to be defined in a Makefile which includes this
 # one and override "common-build" without override warnings.
 %: common-% ;
 
+.PHONY: common-all
+common-all: precheck style check_license staticcheck unused build test
+
 .PHONY: common-style
 common-style:
 	@echo ">> checking code style"