Remove OpenJDK-alpine Dockerfile template

Changelog: deprecated
Signed-off-by: Takuya Noguchi <takninnovationresearch@gmail.com>

doc/api/templates/dockerfiles.md

@@ -74,10 +74,6 @@ Example response:
     "key": "OpenJDK",
     "name": "OpenJDK"
   },
-  {
-    "key": "OpenJDK-alpine",
-    "name": "OpenJDK-alpine"
-  },
   {
     "key": "PHP",
     "name": "PHP"

vendor/Dockerfile/OpenJDK-alpine.Dockerfile

-FROM openjdk:8-alpine
-
-COPY . /usr/src/myapp
-WORKDIR /usr/src/myapp
-
-RUN javac Main.java
-
-CMD ["java", "Main"]