deps: upgrade threeten to 1.4 (#33)

Author: kolea2

google-cloud-bigtable/pom.xml

@@ -115,8 +115,6 @@
     <dependency>
       <groupId>org.threeten</groupId>
       <artifactId>threetenbp</artifactId>
-      <!-- For dependency convergence with gax -->
-      <version>1.3.3</version>
     </dependency>
     <!-- // TODO(igorbernstein): Enable grpc views once we upgrade to grpc-java 1.24.0 -->
 <!--    <dependency>-->

pom.xml

@@ -162,7 +162,7 @@
         <guava.version>28.1-android</guava.version>
         <opencensus.version>0.24.0</opencensus.version>
         <protobuf.version>3.10.0</protobuf.version>
-        <threeten.version>1.3.3</threeten.version>
+        <threeten.version>1.4.0</threeten.version>
     </properties>
 
     <dependencyManagement>