update CI badge in readme; try to get 1.12 w/ GOPATH mode working

.circleci/config.yml

@@ -1,7 +1,9 @@
-# Use the latest 2.1 version of CircleCI pipeline process engine. See: https://circleci.com/docs/2.0/configuration-reference
-configs:
+shared_configs:
   simple_job_steps: &simple_job_steps
     - checkout
+    #TODO: caching config so we don't accidentally try to re-use
+    #cache across versions of Go...
+
     #- restore_cache:
     #    keys:
     #      - go-mod-v4-{{ checksum "go.sum" }}
@@ -22,14 +24,16 @@ configs:
     #    path: /tmp/test-reports
 
 
+# Use the latest 2.1 version of CircleCI pipeline process engine. See: https://circleci.com/docs/2.0/configuration-reference
 version: 2.1
 jobs:
   build-1-12-gopath:
-    working_directory: ~/repo
+    working_directory: ~/gopath/github.com/jhump/protoreflect
     docker:
       - image: circleci/golang:1.12
     environment:
       GO111MODULE: "off"
+      PATH: ~/gopath
     steps: *simple_job_steps
 
   build-1-12:

README.md

@@ -1,5 +1,5 @@
 # Protocol Buffer and gRPC Reflection
-[![Build Status](https://travis-ci.com/jhump/protoreflect.svg?branch=master)](https://travis-ci.com/github/jhump/protoreflect/branches)
+[![Build Status](https://circleci.com/gh/jhump/protoreflect.svg?style=svg)](https://circleci.com/gh/jhump/protoreflect)
 [![Go Report Card](https://goreportcard.com/badge/github.com/jhump/protoreflect)](https://goreportcard.com/report/github.com/jhump/protoreflect)
 
 This repo provides reflection APIs for [protocol buffers](https://developers.google.com/protocol-buffers/) (also known as "protobufs" for short)