Rename "install_libs" env option to "lib_install"

docs/projectconf.rst

@@ -341,8 +341,8 @@ exclude ``.git`` and ``svn`` repository folders and exclude ``examples`` folder.
 This option can be set by global environment variable
 :ref:`envvar_PLATFORMIO_SRC_FILTER`.
 
-``install_libs``
-^^^^^^^^^^^^^^^^
+``lib_install``
+^^^^^^^^^^^^^^^
 
 Specify dependent libraries which should be installed before environment
 process. The only library IDs are allowed. Multiple libraries can be passed
@@ -355,7 +355,7 @@ Example:
 .. code-block:: ini
 
     [env:depends_on_some_libs]
-    install_libs = 1,13,19
+    lib_install = 1,13,19
 
 ``lib_use``
 ^^^^^^^^^^^