Suppress false positive in gosec

New versions of gosec implemented stricter type conversion.
Since the integer values will be small in the conversions in this codebase,
it is safe to suppress these gosec warnings.

Signed-off-by: David Enyeart <[email protected]>

Author: denyeart

.golangci.yml

@@ -16,3 +16,7 @@ linters:
     - misspell
     - typecheck
     - unused
+linters-settings:
+  gosec:
+    excludes:
+      - 'G115' # safe to exclude type conversion overflow checks in this repository since the integer values will always be low