android build: pin hashes of p4a recipes

contrib/android/p4a_recipes/plyer/__init__.py

@@ -0,0 +1,15 @@
+from pythonforandroid.recipe import PythonRecipe
+
+
+assert PythonRecipe.depends == ['python3']
+assert PythonRecipe.python_depends == []
+
+
+class PlyerRecipePinned(PythonRecipe):
+    version = "2.0.0"
+    sha512sum = "8088eeb41aac753435ff5be9835be74d57a55cf557ad76cbad8026352647e554571fae6172754e39882ea7ef07cc1e97fac16556a4426456de99daebe5cd01cf"
+    url = "https://pypi.python.org/packages/source/p/plyer/plyer-{version}.tar.gz"
+    depends = ["setuptools"]
+
+
+recipe = PlyerRecipePinned()