Bump supported pyfastx versions

The motivation is that version 0.9.0 added support for Python 3.10 and
3.11¹, which we want to support for Augur.

However, 0.9.0 also introduced a bug that prevented access by sequence
ID. This was fixed in version 1.0.0.²

Looking at the rest of the changelog, I don't see any other breaking
changes through the current version (2.0.1), at least for Augur's use
case. Assuming this will hold true for other 2.x versions, allow both
major versions 1 and 2.

¹ https://github.com/lmdu/pyfastx/blob/ee7303d1402d5f83db1a6ec74b5140b912ae75bb/docs/changelog.rst
² lmdu/pyfastx#62

setup.py

@@ -62,7 +62,7 @@
         "packaging >=19.2",
         "pandas >=1.0.0, ==1.*",
         "phylo-treetime >=0.10.0, <0.12",
-        "pyfastx >=0.8.4, ==0.8.*",
+        "pyfastx >=1.0.0, <3.0",
         "scipy ==1.*",
         "xopen[zstd] >=1.7.0, ==1.*"
     ],