Bump github.com/google/go-attestation from 0.2.0 to 0.4.0

Bumps [github.com/google/go-attestation](https://github.com/google/go-attestation) from 0.2.0 to 0.4.0.
- [Release notes](https://github.com/google/go-attestation/releases)
- [Commits](google/go-attestation@v0.2.0...v0.4.0)

---
updated-dependencies:
- dependency-name: github.com/google/go-attestation
  dependency-type: direct:production
...

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

go.mod

@@ -3,27 +3,17 @@ module github.com/bloomberg/spire-tpm-plugin
 go 1.12
 
 require (
-	github.com/google/certificate-transparency-go v1.0.22-0.20190605205155-41fc2ef3a2a8
-	github.com/google/go-attestation v0.2.0
-	github.com/google/go-cmp v0.3.1 // indirect
-	github.com/google/go-tpm-tools v0.1.1
-	github.com/google/go-tspi v0.2.1-0.20190423175329-115dea689aad
+	github.com/google/certificate-transparency-go v1.1.1
+	github.com/google/go-attestation v0.4.0
+	github.com/google/go-tpm-tools v0.3.1
 	github.com/hashicorp/go-immutable-radix v1.1.0 // indirect
-	github.com/hashicorp/go-uuid v1.0.1 // indirect
 	github.com/hashicorp/golang-lru v0.5.3 // indirect
 	github.com/hashicorp/hcl v1.0.0
 	github.com/hashicorp/yamux v0.0.0-20181012175058-2f1d1f20f75d // indirect
-	github.com/konsorten/go-windows-terminal-sequences v1.0.2 // indirect
-	github.com/mitchellh/go-testing-interface v1.0.0 // indirect
-	github.com/prometheus/client_golang v1.1.0 // indirect
-	github.com/prometheus/client_model v0.0.0-20190812154241-14fe0d1b01d4 // indirect
-	github.com/prometheus/procfs v0.0.4 // indirect
 	github.com/sirupsen/logrus v1.4.2
 	github.com/spiffe/spire v0.0.0-20190822230128-9a454825770e
 	github.com/spiffe/spire/proto/spire v0.0.0-20190822230128-9a454825770e
-	github.com/stretchr/testify v1.4.0
+	github.com/stretchr/testify v1.6.1
 	github.com/zeebo/errs v1.2.2 // indirect
-	golang.org/x/net v0.0.0-20190827160401-ba9fcec4b297 // indirect
-	google.golang.org/genproto v0.0.0-20190819201941-24fa4b261c55 // indirect
-	google.golang.org/grpc v1.23.0
+	google.golang.org/grpc v1.29.1
 )