fix android build errors

[michaelknoch]

I was facing build errors on my local machine and on linux ci.

Task :react-native-search-bar:processDebugAndroidTestManifest FAILED
FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':react-native-search-bar:processDebugAndroidTestManifest'.
> Manifest merger failed : uses-sdk:minSdkVersion 1 cannot be smaller than version 16 declared in library [com.facebook.react:react-native:0.62.2] /root/.gradle/caches/transforms-2/files-2.1/fb1b10f067852cd6c3178d2de46b96d8/AndroidManifest.xml as the library might be using APIs not available in 1
  	Suggestion: use a compatible library with a minSdk of at most 1,
  		or increase this project's minSdk version to at least 16,
  		or use tools:overrideLibrary="com.facebook.react" to force usage (may lead to runtime failures)

Setting a minSdkVersion in the library build.gradle fixed the issue. This also seems to be a best practice to avoid build issues. @umhan35