0.13.1 Multiple test plans support

What's Changed

• Support multiple test plans by @mikeger in #67

Full Changelog: 0.12.8...0.13.1

Binary artifactbundle

.binaryTarget(
  name: "xcode-selective-test",
  url: "https://github.com/mikeger/XcodeSelectiveTesting/releases/download/0.13.1/xcode-selective-test.artifactbundle.zip",
  checksum: "7ed9e7cb7164a047503bf4dbc60f41d8362cdb0312492424b109612fa94fff84"
)