chore: setup Release Please (#148)

* chore: setup Release Please

This creates PRs that can be merged to create GitHub Releases for each
of the components of Functions Framework Java.

Author: anniefu

.github/.release-please-manifest.json

@@ -0,0 +1 @@
+{"functions-framework-api":"1.0.4","invoker":"1.1.1","function-maven-plugin":"0.10.1"}

.github/release-please-config.json

@@ -0,0 +1,73 @@
+{
+    "separate-pull-requests": true,
+    "packages": {
+        "functions-framework-api": {
+            "release-type": "maven",
+            "component": "functions-framework-api",
+            "extra-files": [
+                {
+                    "type": "xml",
+                    "path": "pom.xml",
+                    "xpath": "//*[local-name()='artifactId' and text()='functions-framework-api']/parent::*/*[local-name()='version']"
+                }
+            ]
+        },
+        "invoker": {
+            "release-type": "maven",
+            "component": "java-function-invoker",
+            "extra-files": [
+                {
+                    "type": "xml",
+                    "path": "pom.xml",
+                    "xpath": "//*[local-name()='artifactId' and text()='java-function-invoker-parent']/parent::*/*[local-name()='version']"
+                },
+                {
+                    "type": "xml",
+                    "path": "core/pom.xml",
+                    "xpath": "//*[local-name()='artifactId' and text()='java-function-invoker-parent']/parent::*/*[local-name()='version']"
+                },
+                {
+                    "type": "xml",
+                    "path": "core/pom.xml",
+                    "xpath": "//*[local-name()='artifactId' and text()='java-function-invoker']/parent::*/*[local-name()='version']"
+                },
+                {
+                    "type": "xml",
+                    "path": "core/pom.xml",
+                    "xpath": "//*[local-name()='artifactId' and text()='java-function-invoker-testfunction']/parent::*/*[local-name()='version']"
+                },
+                {
+                    "type": "xml",
+                    "path": "conformance/pom.xml",
+                    "xpath": "//*[local-name()='artifactId' and text()='java-function-invoker-parent']/parent::*/*[local-name()='version']"
+                },
+                {
+                    "type": "xml",
+                    "path": "conformance/pom.xml",
+                    "xpath": "//*[local-name()='artifactId' and text()='conformance']/parent::*/*[local-name()='version']"
+                },
+                {
+                    "type": "xml",
+                    "path": "testfunction/pom.xml",
+                    "xpath": "//*[local-name()='artifactId' and text()='java-function-invoker-parent']/parent::*/*[local-name()='version']"
+                },
+                {
+                    "type": "xml",
+                    "path": "testfunction/pom.xml",
+                    "xpath": "//*[local-name()='artifactId' and text()='java-function-invoker-testfunction']/parent::*/*[local-name()='version']"
+                }
+            ]
+        },
+        "function-maven-plugin": {
+            "release-type": "maven",
+            "component": "function-maven-plugin",
+            "extra-files": [
+                {
+                    "type": "xml",
+                    "path": "pom.xml",
+                    "xpath": "//*[local-name()='artifactId' and text()='function-maven-plugin']/parent::*/*[local-name()='version']"
+                }
+            ]
+        }
+    }
+}

.github/release-please.yml

@@ -0,0 +1,5 @@
+handleGHRelease: true
+monorepoTags: true
+manifest: true
+manifestConfig: '.github/release-please-config.json'
+manifestFile: '.github/.release-please-manifest.json'