Create requirements.txt

Currently the inference throws the `issubclass() arg 1 must be a class`error which is likely related to incorrect pydantic/spacy version. More context: https://github.com/explosion/spaCy/issues/12659
Trying to ping the versions.

requirements.txt

@@ -0,0 +1,2 @@
+pydantic>=1.7.4,!=1.8,!=1.8.1,<3.0.0
+spacy>=3.7.2,<3.8.0