chore(deps): update dependency com.squareup.okhttp3:mockwebserver to v4.7.2

[renovate]

This PR contains the following updates:

Package	Update	Change
com.squareup.okhttp3:mockwebserver (source)	minor	4.6.0 -> 4.7.2

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Release Notes

square/okhttp

v4.7.2

2020-05-20

• Fix: Don't crash inspecting whether the host platform is JVM or Android. With 4.7.0 and 4.7.1 we
  had a crash IllegalArgumentException: Not a Conscrypt trust manager because we depended on
  initialization order of companion objects.

v4.7.1

2020-05-18

• Fix: Pass the right arguments in the trust manager created for addInsecureHost(). Without the
  fix insecure hosts crash with an IllegalArgumentException on Android.

v4.7.0

2020-05-17

• New: HandshakeCertificates.Builder.addInsecureHost() makes it easy to turn off security in
  private development environments that only carry test data. Prefer this over creating an
  all-trusting TrustManager because only hosts on the allowlist are insecure. From
  [our DevServer sample][dev_server]:

  val clientCertificates = HandshakeCertificates.Builder()
      .addPlatformTrustedCertificates()
      .addInsecureHost("localhost")
      .build()
  
  val client = OkHttpClient.Builder()
      .sslSocketFactory(clientCertificates.sslSocketFactory(), clientCertificates.trustManager)
      .build()

• New: Add cacheHit, cacheMiss, and cacheConditionalHit() events to EventListener. Use
  these in logs, metrics, and even test cases to confirm your cache headers are configured as
  expected.

• New: Constant string okhttp3.VERSION. This is a string like "4.5.0-RC1", "4.5.0", or
  "4.6.0-SNAPSHOT" indicating the version of OkHttp in the current runtime. Use this to include
  the OkHttp version in custom User-Agent headers.

• Fix: Don't crash when running as a plugin in Android Studio Canary 4.1. To enable
  platform-specific TLS features OkHttp must detect whether it's running in a JVM or in Android.
  The upcoming Android Studio runs in a JVM but has classes from Android and that confused OkHttp!

• Fix: Include the header Accept: text/event-stream for SSE calls. This header is not added if
  the request already contains an Accept header.

• Fix: Don't crash with a NullPointerException if a server sends a close while we're sending a
  ping. OkHttp had a race condition bug.

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