Bump firestore version for release (#530)

Additionally fix pom filter to exclude multidex from deps.

Author: vkryachko

buildSrc/src/main/groovy/com/google/firebase/gradle/plugins/publish/Publisher.groovy

@@ -74,7 +74,7 @@ class Publisher {
         pom.dependencies.dependency.each {
             // remove multidex as it is supposed to be added by final applications and is needed for
             // some libraries only for instrumentation tests to build.
-            if (it.groupId.text() in ['com.android.support', 'androidx'] && it.artifactId.text() == 'multidex') {
+            if (it.groupId.text() in ['com.android.support', 'androidx.multidex'] && it.artifactId.text() == 'multidex') {
                 it.parent().remove(it)
             }
             it.appendNode('type', [:], deps["${it.groupId.text()}:${it.artifactId.text()}"])

firebase-firestore/gradle.properties

@@ -1,2 +1,2 @@
-version=20.0.1
+version=20.1.0
 latestReleasedVersion=20.0.0