Raise an error if the securityScheme to be referenced does not exist.

[k1LoW]

Hi there.

I fixed a problem when the securityScheme to be referenced does not exist.

--- FAIL: TestParamValidator_ValidateSecurity_MissingSecuritySchemes (0.00s)
panic: runtime error: invalid memory address or nil pointer dereference [recovered]
        panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x2 addr=0x0 pc=0x10242c5d8]

goroutine 733 [running]:
testing.tRunner.func1.2({0x1025a04a0, 0x1029ea420})
        /Users/k1low/sdk/go1.22.1/src/testing/testing.go:1631 +0x1c4
testing.tRunner.func1()
        /Users/k1low/sdk/go1.22.1/src/testing/testing.go:1634 +0x33c
panic({0x1025a04a0?, 0x1029ea420?})
        /Users/k1low/sdk/go1.22.1/src/runtime/panic.go:770 +0x124
github.com/pb33f/libopenapi-validator/parameters.(*paramValidator).ValidateSecurity(0x14000377f20, 0x140003b6ea0)
        /Users/k1low/src/github.com/pb33f/libopenapi-validator/parameters/validate_security.go:58 +0x198
github.com/pb33f/libopenapi-validator/parameters.TestParamValidator_ValidateSecurity_MissingSecuritySchemes(0x1400010e340)
        /Users/k1low/src/github.com/pb33f/libopenapi-validator/parameters/validate_security_test.go:314 +0xa4
testing.tRunner(0x1400010e340, 0x102687aa0)
        /Users/k1low/sdk/go1.22.1/src/testing/testing.go:1689 +0xec
created by testing.(*T).Run in goroutine 1
        /Users/k1low/sdk/go1.22.1/src/testing/testing.go:1742 +0x318
FAIL    github.com/pb33f/libopenapi-validator/parameters        0.585s

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.96%. Comparing base (29ed98d) to head (dd580b2).

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #61   +/-   ##
=======================================
  Coverage   98.96%   98.96%           
=======================================
  Files          19       19           
  Lines        1156     1157    +1     
=======================================
+ Hits         1144     1145    +1     
  Misses         12       12           

Flag	Coverage Δ
unittests	98.96% <100.00%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[daveshanley]

LGTM thank you for your contribution.