Update rdflib requirement from <6.2,>=4.2.2 to >=4.2.2,<6.3 (#1698)

Updates the requirements on [rdflib](https://github.com/RDFLib/rdflib) to permit the latest version.
- [Release notes](https://github.com/RDFLib/rdflib/releases)
- [Changelog](https://github.com/RDFLib/rdflib/blob/master/CHANGELOG.md)
- [Commits](RDFLib/rdflib@4.2.2...6.2.0)

---
updated-dependencies:
- dependency-name: rdflib
  dependency-type: direct:production
...

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements.txt

@@ -1,6 +1,6 @@
 requests>=2.4.3
 ruamel.yaml>=0.15,<0.17.22
-rdflib>=4.2.2,<6.2
+rdflib>=4.2.2,<6.3
 rdflib>= 4.2.2, < 6.0.0;python_version<='3.6'
 shellescape>=3.4.1,<3.9
 schema-salad>=8.2.20211104054942,<9

setup.py

@@ -109,7 +109,7 @@
         "requests >= 2.6.1",  # >= 2.6.1 to workaround
         # https://github.com/ionrock/cachecontrol/issues/137
         "ruamel.yaml >= 0.15, < 0.17.22",
-        "rdflib >= 4.2.2, < 6.2.0",
+        "rdflib >= 4.2.2, < 6.3.0",
         "rdflib >= 4.2.2, < 6.0.0;python_version<='3.6'",
         "shellescape >= 3.4.1, < 3.9",
         "schema-salad >= 8.2.20211104054942, < 9",