Update py-solc-x requirement from <2.0.0 to <3.0.0

Updates the requirements on [py-solc-x](https://github.com/ApeWorX/py-solc-x) to permit the latest version.
- [Release notes](https://github.com/ApeWorX/py-solc-x/releases)
- [Changelog](https://github.com/ApeWorX/py-solc-x/blob/main/CHANGELOG.md)
- [Commits](https://github.com/ApeWorX/py-solc-x/compare/v0.1.0...v2.0.3)

---
updated-dependencies:
- dependency-name: py-solc-x
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

requirements.txt

@@ -16,7 +16,7 @@ numpy
 persistent>=4.2.0
 py-flags
 py-evm==0.10.1b1
-py-solc-x<2.0.0
+py-solc-x<3.0.0
 py-solc
 pyparsing>=2.0.2,<4
 requests