VAULT-5827 Update mongodb, brotli
Closes https://github.com/hashicorp/vault-plugin-secrets-mongodbatlas/issues/11
* `brotli` 1.0.1 was withdrawn
* `go-client-mongodb-atlas` has an old dependency on a renamed repo, and
has been renamed twice. This caused issues in
https://github.com/hashicorp/vault-plugin-secrets-mongodbatlas/issues/11
for example.
* VAULT-5827 Set unwrap token during database tests
The unwrap token is necessary for the plugins to start correctly when
running when running acceptance tests locally, e.g.,
```
$ VAULT_MONGODBATLAS_PROJECT_ID=... VAULT_MONGODBATLAS_PRIVATE_KEY=... VAULT_MONGODBATLAS_PUBLIC_KEY=... TEST='-run TestBackend_StaticRole_Rotations_MongoDBAtlas github.com/hashicorp/vault/builtin/logical/database' make test
--- FAIL: TestBackend_StaticRole_Rotations_MongoDBAtlas (5.33s)
rotation_test.go:818: err:%!s(<nil>) resp:&logical.Response{Secret:<nil>, Auth:<nil>, Data:map[string]interface {}{"error":"error creating database object: invalid database version: 2 errors occurred:\n\t* Unrecognized remote plugin message: PASS\n\nThis usually means that the plugin is either invalid or simply\nneeds to be recompiled to support the latest protocol.\n\t* Incompatible API version with plugin. Plugin version: 5, Client versions: [3 4]\n\n"}, Redirect:"", Warnings:[]string(nil), WrapInfo:(*wrapping.ResponseWrapInfo)(nil), Headers:map[string][]string(nil)}
```
Note the `PASS` message there, which indicates that the plugin exited
before starting the RPC server.
457f28240e