Switch from unmaintained gothub uploader to github-release

Change-Id: I76c7590948daf7ff30de99268b2011fb1089252b
diff --git a/packer/provision/basebuild.sh b/packer/provision/basebuild.sh
index 95d0307..18f2d89 100644
--- a/packer/provision/basebuild.sh
+++ b/packer/provision/basebuild.sh
@@ -193,8 +193,8 @@
     go get -v github.com/t-yuki/gocover-cobertura
     go get -v github.com/jstemmer/go-junit-report
 
-    # gothub - uploader for github artifacts
-    go get -v github.com/itchio/gothub
+    # github-release - uploader for github artifacts
+    go get -v github.com/github-release/github-release
 
     # dep for go package dependencies w/versioning, version 0.5.2, adapted from:
     #  https://golang.github.io/dep/docs/installation.html#install-from-source