docs: add a security policy file to report bugs

[kdenhartog]

Description

Adds Mattr's security policy with a way to contact us for responsible disclosure

• [ ] Tests for the changes have been added (for bug fixes / features)
• [ ] The commit message(s) follow conventional commits
• [X] Documentation has been added / updated (for bug fixes / features)
• [ ] Changes follow the contributing document.

Motivation and Context

So security researchers can responsibly disclose vulnerabilities to us.

Does this PR introduce a breaking change?

• [ ] Yes
• [X] No

Which merge strategy will you use?

• [X] Squash
• [ ] Rebase (REVIEW COMMITS)

[github-actions[bot]]

Total Coverage: 86.96%

Coverage Report

File	Branches	Funcs	Lines	Uncovered Lines
src
bbsSignature.ts	100%	72.73%	80.95%	143, 167, 220, 221, 222, 229, 240, 241, 258, 259, 260, 268
bls12381.ts	83.33%	100%	100%	29
bls12381toBbs.ts	100%	100%	100%
index.ts	100%	100%	100%
src/types
BlsKeyPair.ts	100%	100%	100%
index.ts	100%	100%	100%

[github-actions[bot]]

Total Coverage: 86.96%

Coverage Report

File	Branches	Funcs	Lines	Uncovered Lines
src
bbsSignature.ts	100%	72.73%	80.95%	143, 167, 220, 221, 222, 229, 240, 241, 258, 259, 260, 268
bls12381.ts	83.33%	100%	100%	29
bls12381toBbs.ts	100%	100%	100%
index.ts	100%	100%	100%
src/types
BlsKeyPair.ts	100%	100%	100%
index.ts	100%	100%	100%

[github-actions[bot]]

Total Coverage: 86.96%

Coverage Report

File	Branches	Funcs	Lines	Uncovered Lines
src
bbsSignature.ts	100%	72.73%	80.95%	143, 167, 220, 221, 222, 229, 240, 241, 258, 259, 260, 268
bls12381.ts	83.33%	100%	100%	29
bls12381toBbs.ts	100%	100%	100%
index.ts	100%	100%	100%
src/types
BlsKeyPair.ts	100%	100%	100%
index.ts	100%	100%	100%

[github-actions[bot]]

Total Coverage: 86.96%

Coverage Report

File	Branches	Funcs	Lines	Uncovered Lines
src
bbsSignature.ts	100%	72.73%	80.95%	143, 167, 220, 221, 222, 229, 240, 241, 258, 259, 260, 268
bls12381.ts	83.33%	100%	100%	29
bls12381toBbs.ts	100%	100%	100%
index.ts	100%	100%	100%
src/types
BlsKeyPair.ts	100%	100%	100%
index.ts	100%	100%	100%

[github-actions[bot]]

Total Coverage: 86.96%

Coverage Report

File	Branches	Funcs	Lines	Uncovered Lines
src
bbsSignature.ts	100%	72.73%	80.95%	143, 167, 220, 221, 222, 229, 240, 241, 258, 259, 260, 268
bls12381.ts	83.33%	100%	100%	29
bls12381toBbs.ts	100%	100%	100%
index.ts	100%	100%	100%
src/types
BlsKeyPair.ts	100%	100%	100%
index.ts	100%	100%	100%

[github-actions[bot]]

Total Coverage: 86.96%

Coverage Report

File	Branches	Funcs	Lines	Uncovered Lines
src
bbsSignature.ts	100%	72.73%	80.95%	143, 167, 220, 221, 222, 229, 240, 241, 258, 259, 260, 268
bls12381.ts	83.33%	100%	100%	29
bls12381toBbs.ts	100%	100%	100%
index.ts	100%	100%	100%
src/types
BlsKeyPair.ts	100%	100%	100%
index.ts	100%	100%	100%

[github-actions[bot]]

Total Coverage: 86.96%

Coverage Report

File	Branches	Funcs	Lines	Uncovered Lines
src
bbsSignature.ts	100%	72.73%	80.95%	143, 167, 220, 221, 222, 229, 240, 241, 258, 259, 260, 268
bls12381.ts	83.33%	100%	100%	29
bls12381toBbs.ts	100%	100%	100%
index.ts	100%	100%	100%
src/types
BlsKeyPair.ts	100%	100%	100%
index.ts	100%	100%	100%

[github-actions[bot]]

Total Coverage: 86.96%

Coverage Report

File	Branches	Funcs	Lines	Uncovered Lines
src
bbsSignature.ts	100%	72.73%	80.95%	143, 167, 220, 221, 222, 229, 240, 241, 258, 259, 260, 268
bls12381.ts	83.33%	100%	100%	29
bls12381toBbs.ts	100%	100%	100%
index.ts	100%	100%	100%
src/types
BlsKeyPair.ts	100%	100%	100%
index.ts	100%	100%	100%

[github-actions[bot]]

Total Coverage: 86.96%

Coverage Report

File	Branches	Funcs	Lines	Uncovered Lines
src
bbsSignature.ts	100%	72.73%	80.95%	143, 167, 220, 221, 222, 229, 240, 241, 258, 259, 260, 268
bls12381.ts	83.33%	100%	100%	29
bls12381toBbs.ts	100%	100%	100%
index.ts	100%	100%	100%
src/types
BlsKeyPair.ts	100%	100%	100%
index.ts	100%	100%	100%

[github-actions[bot]]

Total Coverage: 86.96%

Coverage Report

File	Branches	Funcs	Lines	Uncovered Lines
src
bbsSignature.ts	100%	72.73%	80.95%	143, 167, 220, 221, 222, 229, 240, 241, 258, 259, 260, 268
bls12381.ts	83.33%	100%	100%	29
bls12381toBbs.ts	100%	100%	100%
index.ts	100%	100%	100%
src/types
BlsKeyPair.ts	100%	100%	100%
index.ts	100%	100%	100%