Bump hamcrest-library from 1.3 to 2.1

Bumps [hamcrest-library](https://github.com/hamcrest/JavaHamcrest) from 1.3 to 2.1.
- [Release notes](https://github.com/hamcrest/JavaHamcrest/releases)
- [Changelog](https://github.com/hamcrest/JavaHamcrest/blob/master/CHANGES.md)
- [Commits](hamcrest/JavaHamcrest@hamcrest-java-1.3...v2.1)

Signed-off-by: dependabot[bot] <support@dependabot.com>

Author: dependabot-support

browserup-proxy-core/build.gradle

@@ -86,7 +86,7 @@ dependencies {
     testImplementation 'org.eclipse.jetty:jetty-server:7.6.16.v20140903'
     testImplementation 'org.eclipse.jetty:jetty-servlet:7.6.16.v20140903'
     testImplementation 'org.eclipse.jetty:jetty-servlets:7.6.16.v20140903'
-    testImplementation 'org.hamcrest:hamcrest-library:1.3'
+    testImplementation 'org.hamcrest:hamcrest-library:2.1'
     testImplementation ('org.mock-server:mockserver-netty:3.10.4') {
         exclude(module: 'logback-classic')
         exclude(module: 'netty-codec-socks')

browserup-proxy-mitm/build.gradle

@@ -78,7 +78,7 @@ dependencies {
     testImplementation 'org.apache.logging.log4j:log4j-core:2.8'
     testImplementation 'org.apache.logging.log4j:log4j-slf4j-impl:2.8'
     testImplementation 'org.codehaus.groovy:groovy-all:2.4.16'
-    testImplementation 'org.hamcrest:hamcrest-library:1.3'
+    testImplementation 'org.hamcrest:hamcrest-library:2.1'
     testImplementation 'org.mockito:mockito-core:2.23.4'
     testImplementation 'org.slf4j:jcl-over-slf4j:1.7.22'
 }

browserup-proxy-rest/build.gradle

@@ -79,7 +79,7 @@ dependencies {
     testImplementation 'org.apache.logging.log4j:log4j-slf4j-impl:2.8.2'
     testImplementation 'org.codehaus.groovy:groovy-all:2.4.16'
     testImplementation 'org.codehaus.groovy.modules.http-builder:http-builder:0.7.1'
-    testImplementation 'org.hamcrest:hamcrest-library:1.3'
+    testImplementation 'org.hamcrest:hamcrest-library:2.1'
     testImplementation 'org.mock-server:mockserver-netty:3.10.8'
     testImplementation 'org.mockito:mockito-core:2.23.4'
     testImplementation 'org.seleniumhq.selenium:selenium-api:3.4.0'