Update to rules_go 0.17.1 and bazel 0.23.0 (#462)

diff --git a/.travis.yml b/.travis.yml
index 0ff894e..df0e49d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -14,9 +14,9 @@
 
 before_install:
   - |
-    wget https://github.com/bazelbuild/bazel/releases/download/0.16.0/bazel_0.16.0-linux-x86_64.deb
-    sha256sum -c <<<'1720273534173474796c9d7d8213c360bedf664d43dd844198690b4c78c485eb  bazel_0.16.0-linux-x86_64.deb'
-    sudo dpkg -i bazel_0.16.0-linux-x86_64.deb
+    wget https://github.com/bazelbuild/bazel/releases/download/0.23.0/bazel_0.23.0-linux-x86_64.deb
+    sha256sum -c <<<'6d3f5a2eae9021671a967c362513eaaae979b76e9c725359cb75ee149a92817e  bazel_0.23.0-linux-x86_64.deb'
+    sudo dpkg -i bazel_0.23.0-linux-x86_64.deb
 
 script:
   - |
diff --git a/WORKSPACE b/WORKSPACE
index 1864def..d738ae6 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -1,11 +1,11 @@
 workspace(name = "bazel_gazelle")
 
-load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 
-git_repository(
+http_archive(
     name = "io_bazel_rules_go",
-    remote = "https://github.com/bazelbuild/rules_go",
-    commit = "ed5133c5ef750e9fdba72ad626f283f42d11ef34", # master as of 2019-02-03
+    sha256 = "6776d68ebb897625dead17ae510eac3d5f6342367327875210df44dbe2aeeb19",
+    urls = ["https://github.com/bazelbuild/rules_go/releases/download/0.17.1/rules_go-0.17.1.tar.gz"],
 )
 
 load("@io_bazel_rules_go//go:deps.bzl", "go_register_toolchains", "go_rules_dependencies")