fix: build tag parsing. (#1413)

* fix: build tag parsing.

* chore: lint fixes.

testutils/g501_samples.go

@@ -3,8 +3,9 @@ package testutils
 import "github.com/securego/gosec/v2"
 
 // SampleCodeG501 - Blocklisted import MD5
-var SampleCodeG501 = []CodeSample{
-	{[]string{`
+var (
+	SampleCodeG501 = []CodeSample{
+		{[]string{`
 package main
 
 import (
@@ -19,4 +20,27 @@ func main() {
 	}
 }
 `}, 1, gosec.NewConfig()},
+	}
+
+	// SampleCodeG501BuildTag provides a reportable file if a build tag is
+	// supplied.
+	SampleCodeG501BuildTag = []CodeSample{
+		{[]string{`
+//go:build tag
+
+package main
+
+import (
+	"crypto/md5"
+	"fmt"
+	"os"
+)
+
+func main() {
+	for _, arg := range os.Args {
+		fmt.Printf("%x - %s\n", md5.Sum([]byte(arg)), arg)
+	}
 }
+`}, 2, gosec.NewConfig()},
+	}
+)