Add a new rule to detect integer overflow on integer types conversion

Signed-off-by: Cosmin Cojocar <cosmin@cojocar.ch>

analyzers/util.go

@@ -38,6 +38,7 @@ type SSAAnalyzerResult struct {
 // BuildDefaultAnalyzers returns the default list of analyzers
 func BuildDefaultAnalyzers() []*analysis.Analyzer {
 	return []*analysis.Analyzer{
+		newConversionOverflowAnalyzer("G115", "Type conversion which leads to integer overflow"),
 		newSliceBoundsAnalyzer("G602", "Possible slice bounds out of range"),
 	}
 }