fix: pin cryptography to a version working on manylinux1

cryptography>=3.4 is only usable on manylinux2010+ systems becaus of the lack of a decent rust compiler on older systems.

Furthermore, on i686 system cryptography does not provide wheels at all. Given OpenSSL version in dockross,
this restrict a bit more which version can be built from sources.

Pin version of cryptography to 3.2.x on linux i686/x86_64.

Author: mayeut

requirements-dev.txt

@@ -12,3 +12,11 @@ twine
 virtualenv>=15.0.3
 wheel
 wheeltools
+
+# need to pin cryptography for manylinux1 builds
+# cryptography only provides manylinux2010 wheels since 3.4.0
+# because of the lack of a decent rust compiler on manylinux1
+# Furthermore, the x86 has no wheels at all requiring to build
+# from source. Given OpenSSL version in the dockcross image, this
+# restrict cryptography version to 3.2.x
+cryptography~=3.2.1 ; sys_platform=="linux" and platform_machine in "i386, i486, i586, i686, x86_64"