Merge pull request #1533 from zlaski-semmle/zlaski/cpp370cl

[CPP-370] Non-const format strings: Add change note for the 1.22 release.

Author: jbj

change-notes/1.22/analysis-cpp.md

@@ -13,6 +13,7 @@
 |----------------------------|------------------------|------------------------------------------------------------------|
 | Expression has no effect (`cpp/useless-expression`) | Fewer false positive results | Calls to functions with the `weak` attribute are no longer considered to be side effect free, because they could be overridden with a different implementation at link time. |
 | Suspicious pointer scaling (`cpp/suspicious-pointer-scaling`) | Lower precision | The precision of this query has been reduced to "medium". This coding pattern is used intentionally and safely in a number of real-world projects. Results are no longer displayed on LGTM unless you choose to display them. |
+| Non-constant format string (`cpp/non-constant-format`) | Fewer false positive results | Rewritten using the taint-tracking library. |
 
 ## Changes to QL libraries