Setting .strictSSL(false) does not work for .attach()

I am able to authenticate and get some work item in my RTC https local server setting Request.strictSSL(false), but when I try to .attach() something, it does not works:

Code:

```
var cookies = unirest.jar();
async.waterfall([
(callback) => {
var req = unirest("POST", "https://localhost:9443/ccm/j_security_check")
.headers({
"Content-Type": "application/x-www-form-urlencoded",
})
.strictSSL(false)
.jar(cookies)
.send("j_username=samuel")
.send("j_password=samuel")
.end(function(res) {
if (res.error) throw new Error(res.error);
console.log('logged');
callback();
});
},
(callback) => {
var req = unirest("GET", "https://localhost:9443/ccm/resource/itemName/com.ibm.team.workitem.WorkItem/2")
.headers({
Accept: "application/json",
})
.jar(cookies)
.strictSSL(false)
.end(function(res) {
if (res.error) throw new Error(res.error);
console.log(res.raw_body);
callback();
});
},
(callback) => {
var req = unirest(
"POST",
"https://localhost:9443/ccm/service/com.ibm.team.workitem.service.internal.rest.IAttachmentRestService?projectId=_Jv0jwFXOEeuKc9Bmrq6cOA&multiple=true"
)
.strictSSL(false)
.jar(cookies)
.attach(
"file",
"https://s3.amazonaws.com/cdn.freshdesk.com/data/helpdesk/attachments/production/8075345095/original/nicolas_cage.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAS6FNSMY2WD6T3JNC%2F20210120%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20210120T164143Z&X-Amz-Expires=86400&X-Amz-SignedHeaders=host&X-Amz-Signature=78fd8611c6a7c530937631d0f61d0c412c9a4f0d3d0a100eca919fa495e5c775"
)
.end(function(res) {
if (res.error) {
console.error(res.error);
} else {
console.log('attach worked');
}
});
}
])
```

Output:

```
logged
{...workitem}
{ Error: self signed certificate
at TLSSocket.onConnectSecure (_tls_wrap.js:1058:34)
at TLSSocket.emit (events.js:198:13)
at TLSSocket._finishInit (_tls_wrap.js:636:8) code: 'DEPTH_ZERO_SELF_SIGNED_CERT' }
```

Am I missing something?

Start at the .attach() entry point and trace how its request handles the strictSSL(false) option compared with the preceding requests. Reproduce the shown attachment request against the self-signed RTC server, then verify that the attachment succeeds without the certificate error when strictSSL(false) is set.

Written by the indexing model from the issue text.