[s360] Ignore irrelevant lz4+Python warnings (#8962)

Fixes: https://dev.azure.com/devdiv/DevDiv/_workitems/edit/2051224
Fixes: https://dev.azure.com/devdiv/DevDiv/_workitems/edit/2051225
Fixes: https://dev.azure.com/devdiv/DevDiv/_workitems/edit/2051226
Fixes: https://dev.azure.com/devdiv/DevDiv/_workitems/edit/2052483
Fixes: https://dev.azure.com/devdiv/DevDiv/_workitems/edit/2052484
Fixes: https://dev.azure.com/devdiv/DevDiv/_workitems/edit/2052485

Ignore irrelevant S360 warnings.  They're irrelevant because the
warnings involve code which is run as part of lz4 unit tests, and are
not used by or shipped with .NET for Android:

  * Use of unapproved hash algorithm or API MD5.
    in external/lz4/tests/test-lz4-speed.py
  * Use of unapproved hash algorithm or API SHA1.
    in external/lz4/tests/test-lz4-abi.py
  * Use of unapproved hash algorithm or API SHA1.
    in external/lz4/tests/test-lz4-versions.py

Author: jonpryor

.lgtm.yml

@@ -1,2 +1,6 @@
 queries:
   - exclude: cs/campaign/constantine
+paths:
+  exclude:
+    # we don't ship lz4 tests
+    - external/lz4/tests