deps: update gax.version to v1.49.0, guava to 28.1-android (#13)

* chore(deps): update gax.version to v1.49.0

* deps: update guava to 28.1-android

* deps: specify version for animal-sniffer-annotations

pom.xml

@@ -154,13 +154,14 @@
     <google.core.version>1.91.2</google.core.version>
     <google.api-common.version>1.8.1</google.api-common.version>
     <google.common-protos.version>1.17.0</google.common-protos.version>
-    <gax.version>1.48.1</gax.version>
+    <gax.version>1.49.0</gax.version>
     <grpc.version>1.24.0</grpc.version>
     <protobuf.version>3.10.0</protobuf.version>
     <junit.version>4.12</junit.version>
-    <guava.version>28.0-android</guava.version>
+    <guava.version>28.1-android</guava.version>
     <threeten.version>1.4.0</threeten.version>
     <javax.annotations.version>1.3.2</javax.annotations.version>
+    <animal-sniffer.version>1.18</animal-sniffer.version>
   </properties>
 
   <dependencyManagement>
@@ -248,6 +249,11 @@
         <artifactId>javax.annotation-api</artifactId>
         <version>${javax.annotations.version}</version>
       </dependency>
+      <dependency>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>animal-sniffer-annotations</artifactId>
+        <version>${animal-sniffer.version}</version>
+      </dependency>
 
       <dependency>
         <groupId>junit</groupId>