Bump contrib.go.opencensus.io/exporter/ocagent from 0.4.12 to 0.7.0

Bumps [contrib.go.opencensus.io/exporter/ocagent](https://github.com/census-ecosystem/opencensus-go-exporter-ocagent) from 0.4.12 to 0.7.0.
- [Release notes](https://github.com/census-ecosystem/opencensus-go-exporter-ocagent/releases)
- [Commits](https://github.com/census-ecosystem/opencensus-go-exporter-ocagent/compare/v0.4.12...v0.7.0)

---
updated-dependencies:
- dependency-name: contrib.go.opencensus.io/exporter/ocagent
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

go.mod

@@ -4,7 +4,7 @@ go 1.15
 
 require (
 	contrib.go.opencensus.io/exporter/jaeger v0.1.0
-	contrib.go.opencensus.io/exporter/ocagent v0.4.12
+	contrib.go.opencensus.io/exporter/ocagent v0.7.0
 	github.com/bombsimon/logrusr v1.0.0
 	github.com/docker/spdystream v0.0.0-20170912183627-bc6354cbbc29 // indirect
 	github.com/elazarl/goproxy v0.0.0-20190421051319-9d40249d3c2f // indirect