checksums: use sha256 checksums everywhere

We'd like to use a consistent checksum scheme everywhere so that we can:

    a) incorporate archive checksums into our specs and have a
       consistent hashing algorithm across all specs.

    b) index mirrors with a consistent type of checksum, and not one that
       is dependent on how spack packages are written.

- [x] convert existing md5, sha224, sha512, sha1 checksums to sha256

var/spack/repos/builtin/packages/orthofinder/package.py

@@ -20,7 +20,7 @@ class Orthofinder(Package):
     homepage = "https://github.com/davidemms/OrthoFinder"
     url      = "https://github.com/davidemms/OrthoFinder/releases/download/2.2.0/OrthoFinder-2.2.0.tar.gz"
 
-    version('2.2.0', '4ff585e1eb148fc694a219296fbdd431')
+    version('2.2.0', sha256='7314f3fdfb24d84aa5b9ee27ce9f670df314889c12b8100e4e476c2d21a1c8e7')
 
     depends_on('blast-plus', type='run')
     depends_on('mcl', type='run')