build: remove pylint and requirements from sdist

An sdist should contain metadata and essential files for generating a
built distribution, i.e. wheel.

Signed-off-by: Joshua Lock <jlock@vmware.com>

MANIFEST.in

@@ -18,11 +18,6 @@ recursive-include tests *.cfg
 recursive-include tests *.coveragerc
 recursive-include tests *.pub
 
-# Development related files
-include requirements*.txt
-include pylintrc
-include tuf/api/pylintrc
-
 # Docs
 include docs/conf.py
 recursive-include tuf *.md
@@ -33,3 +28,7 @@ recursive-include docs *.rst
 # To remove
 recursive-include tuf/scripts *.py
 
+# Development related files are not required in sdist
+exclude pylintrc
+exclude tuf/api/pylintrc
+exclude requirements*txt