Add Maven dependency usage to README.md

Author: koder95

README.md

@@ -1,2 +1,12 @@
 # CatholicMoveableFeasts
 A simple and useful generator of important christian dates.
+
+## Usage
+### Maven dependency
+```xml
+<dependency>
+    <groupId>pl.koder95</groupId>
+    <artifactId>cmf</artifactId>
+    <version>0.1.1</version>
+</dependency>
+```