Allow Shebang (#!) line mikefarah#1851

Fairly dirty way of allowing shebang lines

This snippet will read the first two characters of a file passed in to
`yq` and remove the line if it begins with "`#!`". This will allow `yq`
to continue parsing it as though the shebang line was not there.

I was not able to find canonical documentation that the shebang is
limited to a single line or cannot include continuation characters.
However these seem to be accepted truths. See:

https://linux.die.net/man/2/execve

https://en.wikipedia.org/wiki/Shebang_(Unix)#Syntax

cmd/utils.go

@@ -256,6 +256,13 @@ func processArgs(originalArgs []string) (string, []string, error) {
 		if err != nil {
 			return "", nil, err
 		}
+
+        //detect and trim shebang (`#!`) line
+		if string(expressionBytes[0:2]) == "#!" {
+			eos := slices.Index(expressionBytes, '\n')
+			expressionBytes = expressionBytes[eos+1:]
+		}
+
 		expression = string(expressionBytes)
 	}