publish GreptimeDB protobuf for Java using jitpack.io (#4)

java/pom.xml

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>io.greptime</groupId>
+    <artifactId>greptimedb-proto</artifactId>
+    <version>0.1.0</version>
+
+    <properties>
+        <maven.compiler.source>8</maven.compiler.source>
+        <maven.compiler.target>8</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <protobuf.version>3.21.12</protobuf.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.google.protobuf</groupId>
+            <artifactId>protobuf-java</artifactId>
+            <version>${protobuf.version}</version>
+        </dependency>
+    </dependencies>
+</project>

java/src/main/resources/gen.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+
+PROTO_ROOT=../../../../proto
+
+protoc -I=${PROTO_ROOT} --java_out=../java/ \
+  ${PROTO_ROOT}/greptime/v1/column.proto \
+  ${PROTO_ROOT}/greptime/v1/ddl.proto \
+  ${PROTO_ROOT}/greptime/v1/database.proto