fix(deps): update module github.com/lestrrat-go/jwx/v3 to v4 (#297)

This PR contains the following updates:

| Package | Change | [Age](https://docs.renovatebot.com/merge-confidence/) | [Confidence](https://docs.renovatebot.com/merge-confidence/) |
|---|---|---|---|
| [github.com/lestrrat-go/jwx/v3](https://github.com/lestrrat-go/jwx) | `v3.1.0` → `v4.0.0` | ![age](https://developer.mend.io/api/mc/badges/age/go/github.com%2flestrrat-go%2fjwx%2fv3/v4.0.0?slim=true) | ![confidence](https://developer.mend.io/api/mc/badges/confidence/go/github.com%2flestrrat-go%2fjwx%2fv3/v3.1.0/v4.0.0?slim=true) |

---

### Release Notes

<details>
<summary>lestrrat-go/jwx (github.com/lestrrat-go/jwx/v3)</summary>

### [`v4.0.0`](https://github.com/lestrrat-go/jwx/releases/tag/v4.0.0)

[Compare Source](https://github.com/lestrrat-go/jwx/compare/v3.1.0...v4.0.0)

# Changes

v4 has many incompatibilities with v3. To see the full list of differences between
v3 and v4, please read the [Changes-v4.md file](./Changes-v4.md). Coding Agents should read [MIGRATION-v4.md](./MICRATION-v4.md)

v4.0.0 - 19 Apr 2026

- Initial v4 release. Major features:
  - Lighter: Core / Companion module separation. Less dependencies in core.
  - Faster: Use of generics and other optimizations make v4 2x\~3x faster than before.
  - Quantum-Ready: ML-KEM and ML-DSA, HPKE (+Hybrid) are supported through companion modules.
- See Changes-v4.md for a full set of Changes since v3.

</details>

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---------

Co-authored-by: Joakim Olsson <joakim@unbound.se>
Reviewed-on: #297
Co-authored-by: Renovate Bot <renovate@unbound.se>
Co-committed-by: Renovate Bot <renovate@unbound.se>

go.mod

@@ -1,25 +1,17 @@
 module gitlab.com/unboundsoftware/auth0mock
 
-go 1.25.0
+go 1.26.0
 
 require (
 	github.com/alecthomas/kong v1.15.0
 	github.com/google/uuid v1.6.0
-	github.com/lestrrat-go/jwx/v3 v3.1.0
+	github.com/lestrrat-go/jwx/v4 v4.0.0
 	github.com/rs/cors v1.11.1
 )
 
 require (
-	github.com/decred/dcrd/dcrec/secp256k1/v4 v4.4.1 // indirect
-	github.com/goccy/go-json v0.10.6 // indirect
-	github.com/lestrrat-go/blackmagic v1.0.4 // indirect
-	github.com/lestrrat-go/dsig v1.2.1 // indirect
-	github.com/lestrrat-go/dsig-secp256k1 v1.0.0 // indirect
-	github.com/lestrrat-go/httpcc v1.0.1 // indirect
-	github.com/lestrrat-go/httprc/v3 v3.0.5 // indirect
-	github.com/lestrrat-go/option/v2 v2.0.0 // indirect
-	github.com/segmentio/asm v1.2.1 // indirect
+	github.com/lestrrat-go/dsig v1.3.0 // indirect
+	github.com/lestrrat-go/option/v3 v3.0.0-alpha1 // indirect
 	github.com/valyala/fastjson v1.6.10 // indirect
 	golang.org/x/crypto v0.50.0 // indirect
-	golang.org/x/sys v0.43.0 // indirect
 )