Adapt to removal of ConnectionTracingID and ConnectionTracingKey in quic-go v0.59.0

[zeewell]

The recent release of quic-go v0.59.0 (pull request #5521) removed the long-deprecated quic.ConnectionTracingID and quic.ConnectionTracingKey. This change might break compatibility for users relying on these fields within the req project.

Reference: quic-go PR #5521.

[nomad-software]

Yep, it no longer compiles when updating dependencies.

# github.com/imroc/req/v3/internal/http3
vendor/github.com/imroc/req/v3/internal/http3/transport.go:102:41: undefined: quic.ConnectionTracingID
vendor/github.com/imroc/req/v3/internal/http3/transport.go:103:42: undefined: quic.ConnectionTracingID
vendor/github.com/imroc/req/v3/internal/http3/client.go:87:38: undefined: quic.ConnectionTracingID
vendor/github.com/imroc/req/v3/internal/http3/client.go:88:42: undefined: quic.ConnectionTracingID
vendor/github.com/imroc/req/v3/internal/http3/client.go:169:85: undefined: quic.ConnectionTracingID
vendor/github.com/imroc/req/v3/internal/http3/client.go:182:39: undefined: quic.ConnectionTracingKey
vendor/github.com/imroc/req/v3/internal/http3/client.go:182:67: undefined: quic.ConnectionTracingID
vendor/github.com/imroc/req/v3/internal/http3/conn.go:235:73: undefined: quic.ConnectionTracingID
vendor/github.com/imroc/req/v3/internal/http3/conn.go:254:34: undefined: quic.ConnectionTracingKey
vendor/github.com/imroc/req/v3/internal/http3/conn.go:254:62: undefined: quic.ConnectionTracingID
vendor/github.com/imroc/req/v3/internal/http3/conn.go:254:62: too many errors

[enetx]

@nomad-software @zeewell surf