Upgrade gradle and test libraries
diff --git a/.idea/codeStyles/Project.xml b/.idea/codeStyles/Project.xml
index 35a40e4..427a78f 100644
--- a/.idea/codeStyles/Project.xml
+++ b/.idea/codeStyles/Project.xml
@@ -4,15 +4,6 @@
       <option name="PACKAGES_TO_USE_STAR_IMPORTS">
         <value />
       </option>
-      <option name="PACKAGES_IMPORT_LAYOUT">
-        <value>
-          <package name="" alias="false" withSubpackages="true" />
-          <package name="java" alias="false" withSubpackages="true" />
-          <package name="javax" alias="false" withSubpackages="true" />
-          <package name="kotlin" alias="false" withSubpackages="true" />
-          <package name="" alias="true" withSubpackages="true" />
-        </value>
-      </option>
       <option name="NAME_COUNT_TO_USE_STAR_IMPORT" value="2147483647" />
       <option name="NAME_COUNT_TO_USE_STAR_IMPORT_FOR_MEMBERS" value="2147483647" />
       <option name="CODE_STYLE_DEFAULTS" value="KOTLIN_OFFICIAL" />
diff --git a/.idea/runConfigurations.xml b/.idea/runConfigurations.xml
index 7f68460..e497da9 100644
--- a/.idea/runConfigurations.xml
+++ b/.idea/runConfigurations.xml
@@ -3,6 +3,7 @@
   <component name="RunConfigurationProducerService">
     <option name="ignoredProducers">
       <set>
+        <option value="com.android.tools.idea.compose.preview.runconfiguration.ComposePreviewRunConfigurationProducer" />
         <option value="org.jetbrains.plugins.gradle.execution.test.runner.AllInPackageGradleConfigurationProducer" />
         <option value="org.jetbrains.plugins.gradle.execution.test.runner.TestClassGradleConfigurationProducer" />
         <option value="org.jetbrains.plugins.gradle.execution.test.runner.TestMethodGradleConfigurationProducer" />
diff --git a/build.gradle b/build.gradle
index 436db1f..3acb684 100644
--- a/build.gradle
+++ b/build.gradle
@@ -7,6 +7,7 @@
     ext.kotlin_version = '1.4.31'
 
     repositories {
+        mavenCentral()
         jcenter()
         google()
     }
@@ -14,7 +15,7 @@
         //noinspection DifferentKotlinGradleVersion
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
         classpath "com.google.protobuf:protobuf-gradle-plugin:0.8.14"
-        classpath 'com.android.tools.build:gradle:4.1.2'
+        classpath 'com.android.tools.build:gradle:4.2.1'
     }
 }
 
diff --git a/gradle/dependencies.gradle b/gradle/dependencies.gradle
index 752c2d2..bcc29e9 100644
--- a/gradle/dependencies.gradle
+++ b/gradle/dependencies.gradle
@@ -3,9 +3,9 @@
     ext.room_version = "2.3.0-alpha02"
     // http://aosp.opersys.com/xref/android-11.0.0_r27/xref/external/protobuf/java/pom.xml#7
     ext.protobuf_version = "3.9.1"
-    junit4_version = "4.13.1"
+    junit4_version = "4.13.2"
     junit5_version = "5.5.2" // careful, upgrading this can change a Cipher's IV size in tests!?
-    mockk_version = "1.10.2"
+    mockk_version = "1.10.2" // higher versions get us a kotlin version conflict
     espresso_version = "3.3.0"
 }
 
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 9ff0d9f..43550d3 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -3,5 +3,5 @@
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.5.1-all.zip
-distributionSha256Sum=143a28f54f1ae93ef4f72d862dbc3c438050d81bb45b4601eb7076e998362920
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.7.1-all.zip
+distributionSha256Sum=22449f5231796abd892c98b2a07c9ceebe4688d192cd2d6763f8e3bf8acbedeb