Refactor variable initialization in generateBinary function

This commit refactors the way the 'length' variable is initialized in the generateBinary function of the Generator struct in random.go. Notably, it makes use of Go's type inference feature to eliminate the need to explicitly declare the variable type.

random.go

@@ -321,7 +321,7 @@ func (g *Generator) generatePronounceable() (string, error) {
 // generateBinary is executed when Generate() is called with Algorithm set
 // to AlgoBinary
 func (g *Generator) generateBinary() (string, error) {
-	var length int64 = DefaultBinarySize
+	length := DefaultBinarySize
 	if g.config.FixedLength > 0 {
 		length = g.config.FixedLength
 	}