snmp_facts: update docs with dependency constraint (#11185)

(cherry picked from commit 4517b86)

Author: russoz

plugins/modules/snmp_facts.py

@@ -15,7 +15,7 @@
 description:
   - Retrieve facts for a device using SNMP. The facts are inserted to the RV(ansible_facts) key.
 requirements:
-  - pysnmp
+  - pysnmp < 6.2.4 - that version removed components used by this module.
 extends_documentation_fragment:
   - community.general.attributes
   - community.general.attributes.facts