Add maven package in stdlib

Signed-off-by: Alvise <vitalvise@gmail.com>

docs/reference/universe/java/maven.md

@@ -0,0 +1,32 @@
+---
+sidebar_label: maven
+---
+
+# alpha.dagger.io/java/maven
+
+Maven is a build automation tool for Java
+
+```cue
+import "alpha.dagger.io/java/maven"
+```
+
+## maven.#Project
+
+A Maven project
+
+### maven.#Project Inputs
+
+| Name             | Type                    | Description                         |
+| -------------    |:-------------:          |:-------------:                      |
+|*source*          | `dagger.#Artifact`      |Application source code              |
+|*package*         | `struct`                |Extra alpine packages to install     |
+|*env*             | `struct`                |Environment variables                |
+|*phases*          | `*["package"] \| []`    |-                                    |
+|*goals*           | `*[] \| []`             |-                                    |
+|*args*            | `*[] \| []`             |Optional arguments for the script    |
+
+### maven.#Project Outputs
+
+| Name             | Type              | Description              |
+| -------------    |:-------------:    |:-------------:           |
+|*build*           | `struct`          |Build output directory    |