Update Java v1.8.x support in README.md (#146)

Fixes #144. Not adding a test because of following reasons: Can't add the dependency in dgraph4j as it will enforce it for all java versions, which in not what we want. Can't add it in DgraphJavaSample, as people will be looking at it irrespective of java version they use. So, I think its better for it to stay as is. Just the documentation update should be enough to guide people who face problems with Java 1.8.x
dgraph-io · May 19, 2020 · 8589f92 · 8589f92
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diff --git a/README.md b/README.md
@@ -68,6 +68,48 @@ use a different version of this client.
 |     1.0.X      |       1.X.X       |     1.9.X    |
 |    >= 1.1.0    |       2.X.X       |     1.9.X    |
 
+#### Note regarding Java 1.8.x support:
+* If you aren't using gRPC with TLS, then the above version table will work for you with Java
+ 1.8.x too.
+* If you're using gRPC with TLS on Java 1.8.x, then you will need to follow gRPC docs [here
+](https://github.com/grpc/grpc-java/blob/master/SECURITY.md#tls-on-non-android). Basically, it
+ will require you to add the following dependency in your app with correct version for the 
+ corresponding `grpc-netty` version used by `dgraph4j`. You can find out the correct version of 
+ the dependency to use from the version combination table in [this section] in `grpc-netty` docs.
+
+  For maven:
+
+  ```xml
+  <dependency>
+    <groupId>io.netty</groupId>
+    <artifactId>netty-tcnative-boringssl-static</artifactId>
+    <version><!-- See table in gRPC docs for correct version --></version>
+  </dependency>
+  ```
+
+  For Gradle:
+
+  ```groovy
+  compile 'io.netty:netty-tcnative-boringssl-static:<See table in gRPC docs for correct version>'
+  ```
+
+  The following table lists the `grpc-netty` versions used by different `dgraph4j` versions over time, along with the supported versions of `netty-tcnative-boringssl-static` for the corresponding `grpc-netty` version:
+
+  | dgraph4j version  | grpc-netty version | netty-tcnative-boringssl-static version |
+  |:-----------------:|:------------------:|:---------------------------------------:|
+  |    1.0.0-1.2.0    |        1.7.0       |               2.0.6.Final               |
+  |    1.4.0-1.6.0    |        1.10.0      |               2.0.7.Final               |
+  |       1.7.0       |        1.15.0      |               2.0.12.Final              |
+  |    1.7.3-1.7.5    |        1.15.1      |               2.0.12.Final              |
+  |    2.0.0-2.1.0    |        1.22.1      |               2.0.25.Final              |
+  |      20.03.0      |        1.26.0      |               2.0.26.Final              |
+
+  So, for example, if you were using `dgraph4j v20.03.0`, then you would need to use `2.0.26-Final` 
+  as the version for `netty-tcnative-boringssl-static` dependency as suggested by gRPC docs for 
+  `grpc-netty v1.26.0`.
+
+[this section]: https://github.com/grpc/grpc-java/blob/master/SECURITY.md#netty
+
 ## Quickstart
 Build and run the [DgraphJavaSample] project in the `samples` folder, which
 contains an end-to-end example of using the Dgraph Java client. Follow the