fix(deps): upgrade yaml.v2 to v3 and golang.org/x/net

[devfeel]

Summary

• Upgrade gopkg.in/yaml.v2 to v3 (fixes DoS vulnerability)
• Upgrade golang.org/x/net to v0.33.0 (fixes XSS and proxy bypass)
• Keep Go version at 1.21 (no version change)

Security Fixes

This PR resolves the following Dependabot alerts:

Alert	Dependency	Severity	Issue
#10	gopkg.in/yaml.v2	High	YAML parsing CPU/memory consumption
#9	gopkg.in/yaml.v2	Medium	Resource consumption in loop
#11	gopkg.in/yaml.v2	Medium	YAML DoS vulnerability
#24	golang.org/x/net	Medium	HTTP proxy bypass (IPv6 Zone IDs)
#25	golang.org/x/net	Medium	XSS vulnerability

Changes

• Updated import path in config/config_yaml.go
• Updated go.mod dependencies
• Go version remains at 1.21
• All tests pass

Test Plan

• Run go test ./... - all tests pass
• Verify yaml parsing still works correctly
• Confirm Go version is unchanged