deps: bump github.com/dropbox/dropbox-sdk-go-unofficial/v6 from 6.3.0 to 6.4.0 in the go-dependencies group

[dependabot]

Bumps the go-dependencies group with 1 update: github.com/dropbox/dropbox-sdk-go-unofficial/v6.

Updates github.com/dropbox/dropbox-sdk-go-unofficial/v6 from 6.3.0 to 6.4.0

Release notes

Sourced from github.com/dropbox/dropbox-sdk-go-unofficial/v6's releases.

v6.4.0 - 2026-07-15

Added

• Added the dropbox/oauth package with PKCE authorization URL, code exchange, and refresh-token helpers.
• Added web redirect PKCE OAuth helpers with caller-owned CSRF validation.
• Added Python-style OAuth 2 no-redirect and web flows with app-secret support, PKCE mode, legacy token access type compatibility, and option validation.
• Added dropbox.Config.TokenSource for refreshable OAuth token sources.
• Added oauth.GenerateVerifier for generating PKCE code verifiers.
• Added oauth.ScopeOpenID, oauth.ScopeEmail, and oauth.ScopeProfile constants and dropbox/openid identity-flow examples for OpenID Connect.
• Added the dropbox/retry package with a configurable Policy for opt-in automatic retries with exponential backoff.
• Added dropbox.Config.RetryPolicy to enable retries for all calls made by a client. Retries 429 and 503 responses (and configurable 409 Stone error tags), honoring Retry-After headers and retry_after response bodies.

Changed

• Raised the minimum supported Go version to 1.25.
• Pinned CI Go versions.

Resolves #103.

Changelog

Sourced from github.com/dropbox/dropbox-sdk-go-unofficial/v6's changelog.

v6.4.0 - 2026-07-15

Added

• Added the dropbox/oauth package with PKCE authorization URL, code exchange, and refresh-token helpers.
• Added web redirect PKCE OAuth helpers with caller-owned CSRF validation.
• Added Python-style OAuth 2 no-redirect and web flows with app-secret support, PKCE mode, legacy token access type compatibility, and option validation.
• Added dropbox.Config.TokenSource for refreshable OAuth token sources.
• Added oauth.GenerateVerifier for generating PKCE code verifiers.
• Added oauth.ScopeOpenID, oauth.ScopeEmail, and oauth.ScopeProfile constants and dropbox/openid identity-flow examples for OpenID Connect.
• Added the dropbox/retry package with a configurable Policy for opt-in automatic retries with exponential backoff.
• Added dropbox.Config.RetryPolicy to enable retries for all calls made by a client. Retries 429 and 503 responses (and configurable 409 Stone error tags), honoring Retry-After headers and retry_after response bodies.

Changed

• Raised the minimum supported Go version to 1.25.
• Pinned CI Go versions.

Commits

• c03dc80 Prepare v6.4.0 release
• 4870a3e Merge pull request #156 from AndreyVMarkelov/codex/fix-oauth-generator
• f36e19b Fix generated OAuth support
• 9bc185d Merge pull request #155 from dropbox/cguldner-patch-1
• b01d704 Group all GitHub Actions updates into one PR
• b8627e2 Merge pull request #154 from AndreyVMarkelov/readme-retry-clarify
• b2c1e55 docs: support posture, retry docs/changelog, require Go 1.25
• 497cb28 Merge pull request #153 from AndreyVMarkelov/add-retry-policy
• 4580259 Merge pull request #153 from AndreyVMarkelov/add-retry-policy
• 89633d5 Add conservative config-based retry policy
• Additional commits viewable in compare view

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