Roll Python version in table to 3.8. Also suggest other changes.

Author: JimacoMS4

articles/app-service/provision-resource-bicep.md

@@ -109,7 +109,7 @@ To deploy a different language stack, update `linuxFxVersion` with appropriate v
 | **PHP**     | linuxFxVersion="PHP|7.4"                        |
 | **Node.js** | linuxFxVersion="NODE|10.15"                     |
 | **Java**    | linuxFxVersion="JAVA|1.8 |TOMCAT|9.0" |
-| **Python**  | linuxFxVersion="PYTHON|3.7"                     |
+| **Python**  | linuxFxVersion="PYTHON|3.8"                     |
 
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