deps: update dependency com.google.auth:google-auth-library-credentials to v0.20.0 (#86)

Author: renovate-bot

pom.xml

@@ -270,7 +270,7 @@
  <dependency>
  <groupId>com.google.auth</groupId>
  <artifactId>google-auth-library-credentials</artifactId>
- <version>0.19.0</version>
+ <version>0.20.0</version>
  </dependency>
  <dependency>
  <groupId>com.google.cloud</groupId>