Fix JitPack artifact publishing

- Change from 'mvn compile' to 'mvn install' in jitpack.yml
- This ensures artifacts are installed to ~/.m2/repository
- JitPack can now find and publish the built artifacts

Author: wassertim

jitpack.yml

@@ -4,4 +4,4 @@ before_install:
   - sed -i "s/\${dynamodb-toolkit.version}/$VERSION/g" pom.xml
   - sed -i "s/\${dynamodb-toolkit.version}/$VERSION/g" integration-tests/pom.xml
 install:
-  - mvn clean compile -DskipTests=true
+  - mvn clean install -DskipTests=true