Typo. Fixes #271

Author: FrancescAlted

README.rst

@@ -83,7 +83,7 @@ Installing via setuptools
 .. code-block:: console
 
     $ python -m pip install -r requirements-dev.txt
-    $ python setup.py build --inplace
+    $ python setup.py build_ext --inplace
 
 Any codec can be enabled (`=1`) or disabled (`=0`) on this build-path with the appropriate
 OS environment variables `INCLUDE_LZ4`, `INCLUDE_SNAPPY`, `INCLUDE_ZLIB`, and
@@ -121,13 +121,13 @@ Using an environment variable:
 
     $ export USE_SYSTEM_BLOSC=1                 # or "set USE_SYSTEM_BLOSC=1" on Windows
     $ export Blosc_ROOT=/usr/local/customprefix # If you installed Blosc into a custom location
-    $ python setup.py build --inplace
+    $ python setup.py build_ext --inplace
 
 Using flags:
 
 .. code-block:: console
 
-    $ python setup.py build --inplace -DUSE_SYSTEM_BLOSC:BOOL=YES -DBlosc_ROOT:PATH=/usr/local/customprefix
+    $ python setup.py build_ext --inplace -DUSE_SYSTEM_BLOSC:BOOL=YES -DBlosc_ROOT:PATH=/usr/local/customprefix
 
 
 Testing