fix(deps): update dependency pointycastle to v4

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
pointycastle	dependencies	major	^3.7.3 → ^4.0.0

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Warning

Some dependencies could not be looked up. Check the Dependency Dashboard for more information.

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Release Notes

bcgit/pc-dart (pointycastle)

v4.0.0

• Add support for utf-16 in ans1_bmp_string.dart
• Add new oid for secp256r1 (PR #​249)
• Fix nullsafety error in padded_block_cipher_impl.dart (PR #​254)
• Fix ASN1Parser length parsing (PR #​250)
• Remove unused js dependency (PR #​251)
• Add new oids (PR #​240)
• Add new oids for elliptic curves (PR #​242)
• Add Blowfish, Camellia, Twofish block cipher engines (PR #​246)
• Reformat CHANGELOG.md to match markdown standards
• Add factory for SHA512 in RSA-OAEP (PR #​227)
• Add generics to generateKeyPair #​191

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⚠️ Artifact update problem

Renovate failed to update an artifact related to this branch. You probably do not want to merge this PR as-is.

♻ Renovate will retry this branch, including artifacts, only when one of the following happens:

• any of the package files in this branch needs updating, or
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The artifact failure details are included below:

File name: mobile/pubspec.lock

Command failed: flutter pub upgrade pointycastle
Because nostr 1.5.0 depends on pointycastle ^3.7.3 and no versions of nostr match >1.5.0 <2.0.0, nostr ^1.5.0 requires pointycastle ^3.7.3.
So, because sprout_mobile depends on both nostr ^1.5.0 and pointycastle ^4.0.0, version solving failed.


You can try one of the following suggestions to make the pubspec resolve:
* Try upgrading your constraint on nostr: flutter pub add nostr:^2.0.0
* Consider downgrading your constraint on pointycastle: flutter pub add pointycastle:^3.9.1
Failed to update packages.

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