Minor syntax fix

.. is required for fetching files from parent dir ... without .. it throws error

Author: ketul93

README.md

@@ -95,7 +95,7 @@ cmake -DBUILD_JNI=TRUE
 The GStreamer plugin and samples are NOT built by default.  If you wish to build them you MUST add -DBUILD_GSTREAMER_PLUGIN=TRUE when running cmake:
 
 ```
-cmake -DBUILD_GSTREAMER_PLUGIN=TRUE
+cmake -DBUILD_GSTREAMER_PLUGIN=TRUE ..
 ```
 
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