bump to golang 1.10 (#3856)

.travis.yml

@@ -3,7 +3,7 @@ sudo: false
 language: go
 
 go:
-- 1.9.x
+- 1.10.x
 - 1.x
 
 go_import_path: github.com/prometheus/prometheus

README.md

@@ -57,7 +57,7 @@ Prometheus will now be reachable at http://localhost:9090/.
 ### Building from source
 
 To build Prometheus from the source code yourself you need to have a working
-Go environment with [version 1.9 or greater installed](http://golang.org/doc/install).
+Go environment with [version 1.10 or greater installed](http://golang.org/doc/install).
 
 You can directly use the `go` tool to download and install the `prometheus`
 and `promtool` binaries into your `GOPATH`:

circle.yml

@@ -2,7 +2,7 @@ machine:
   environment:
     DOCKER_IMAGE_NAME: prom/prometheus
     QUAY_IMAGE_NAME: quay.io/prometheus/prometheus
-    DOCKER_TEST_IMAGE_NAME: quay.io/prometheus/golang-builder:1.9-base
+    DOCKER_TEST_IMAGE_NAME: quay.io/prometheus/golang-builder:1.10-base
     REPO_PATH: github.com/prometheus/prometheus
   pre:
     - sudo curl -L -o /usr/bin/docker 'https://s3-external-1.amazonaws.com/circle-downloads/docker-1.9.1-circleci'