Update README.md (#107)

* Update README.md

While trying to use this library in a Gradle project, I was running into the error "Unable to access CRS file: proj4/nad/epsg". I noticed the note for Maven projects to add the epsg dependency, so tried adding it to my Gradle dependencies and it solved the problem.

* Update README.md

Make Gradle section similar to Maven section

README.md

@@ -48,6 +48,9 @@ where `{latest version}` refers to the version indicated by the badge above.
 
 ### Using Proj4J with Gradle
 
+**!Important!** As of `1.2.2` version, `proj4-core` contains no EPSG Licensed files. 
+In order to make proj4j properly operate, it makes sense to consider `proj4-epsg` dependency usage.
+
 To include Proj4J in a Gradle project, add a dependency block like the following:
 
 ```
@@ -57,6 +60,17 @@ dependencies {
 ```
 where `{latest version}` refers to the version indicated by the badge above.
 
+#### Proj4j EPSG
+
+`Proj4J-EPSG` module distributes a portion of the EPSG dataset. This artifact is released the [EPSG database distribution license](https://raw.githubusercontent.com/locationtech/proj4j/master/LICENSE.EPSG).
+
+To include `Proj4J-EPSG` in a Gradle project, add the following line to the dependency block:
+
+```
+    implementation 'org.locationtech.proj4j:proj4j-epsg:{latest version}'
+```
+where `{latest version}` refers to the version indicated by the badge above.
+
 ### Basic Usage
 
 The following examples give a quick intro on how to use Proj4J in common