[BUG] salt.utils.aws.sig4 force usage of version as GET parameters even if method is not GET

Description
A clear and concise description of what the bug is.

** Setup
No Setup required

Steps to Reproduce the behavior

from salt.utils.aws import sig4
import requests

method = "POST"
body="Action=GetCallerIdentity&Version=2011-06-15"
endpoint="sts.amazonaws.com"
location="us-east-1"
params = {}
version = "2011-06-15"
product = "sts"
provider = {'id': 'use-instance-role-credentials', 'key': 'use-instance-role-credentials'}
hd = {"Content-Type": "application/x-www-form-urlencoded; charset=utf-8"}
headers, requests_url = sig4(   method=method, 
                                endpoint=endpoint,
                                prov_dict=provider,
                                params=params,
                                product="sts",
                                data=body,
                                aws_api_version=version,
                                location=location,
                                requesturl=f"https://{endpoint}/",
                                headers=hd
                            )
print(requests_url)
# https://sts.amazonaws.com?Version=2011-06-15
print(headers)
# {'Content-Type': 'application/x-www-form-urlencoded; charset=utf-8', 'X-Amz-date': '20211116T160158Z', 'host': 'sts.amazonaws.com', 'x-amz-content-sha256': 'ab821ae955788b0e33ebd34c208442ccfc2d406e2edc5e7a39bd6458fbb4f843', 'X-Amz-security-token': '<redacted>', 'Authorization': 'AWS4-HMAC-SHA256 Credential=<redacted>/20211116/us-east-1/sts/aws4_request, SignedHeaders=content-type;host;x-amz-content-sha256;x-amz-date;x-amz-security-token, Signature=<redacted>'}
r = requests.post(requests_url,headers= headers, data=body) # https://sts.amazonaws.com/?Version=2011-06-15
print(r.status_code)
# 400
print(r.text)
# ... When Content-Type:application/x-www-form-urlencoded, URL cannot include query-string parameters (after \'?\'): \'/?Version=2011-06-15\' ...
r = requests.post("https://sts.amazonaws.com/",headers= headers, data=body) # Manually remove GET parameters
print(r.status_code)
# 403
print(r.text)
# The request signature we calculated does not match the signature you provided. Check your AWS Secret Access Key and signing method. Consult the service documentation for details.
params = {"Action":"GetCallerIdentity", "Version": "2011-06-15"}
method = "GET"
hd = {}
body=""
headers, requests_url = sig4(   method=method, 
                                endpoint=endpoint,
                                prov_dict=provider,
                                params=params,
                                product="sts",
                                data=body,
                                aws_api_version=version,
                                location=location,
                                requesturl=f"https://{endpoint}/",
                                headers=hd
                            )
print(requests_url)
# https://sts.amazonaws.com/?Action=GetCallerIdentity&Version=2011-06-15
r = requests.get(requests_url,headers= headers)
print(r.status_code)
# 200

Expected behavior
request_url should not contains any params when not using GET method and then query_string should be empty in order to have a valid aws sig4 signature

Versions Report

</details>

Start with salt.utils.aws.sig4 and run the POST and GET reproductions from the issue against the shown AWS STS endpoint. Trace how aws_api_version and params become the request URL and signed query string; done means non-GET requests have no query parameters and produce a valid AWS SigV4 signature while GET behavior remains valid.