Update pinned dependencies to latest released versions

[herbie-bot]

Goal

Bump the dependency versions that this project pins directly in pom.xml to their latest fixed released versions. One-time maintenance task.

Scope

Only the six versions declared in the <properties> block of the root pom.xml:

• slack-api-client — currently 1.45.3
• swagger-annotations-jakarta — currently 2.2.29
• jspecify — currently 1.0.0
• testcontainers — currently 2.0.5
• wiremock — currently 3.10.0
• mcp-sdk — currently 0.18.3 (drives both mcp-spring-webmvc and mcp-json-jackson2)

Out of scope: Spring Boot, Spring Security, Jackson, the Java version, and the com.open-elements:java-parent parent — these are version-managed by the parent POM/BOM and are not part of this task.

Constraints

• MCP SDK: Stay on the latest release of the 0.18.x line that still carries the mcp-spring-webmvc (WebMVC Streamable HTTP) transport. Do not upgrade to the 2.x track — it drops the transport this project depends on. Upgrade only to a version that fulfills our needs.
• Released versions only: Every new version must be a fixed, released artifact. No SNAPSHOT, no -RC, no milestone releases.
• Reproducible builds: Each bump is a concrete pinned value — no version ranges or floating versions.
• No automation: This is a one-time manual bump. Setting up Dependabot/Renovate is explicitly out of scope for now.

Acceptance criteria

• All applicable pinned versions updated to their latest released versions (within the constraints above).
• build.yml CI passes green with the new versions.

The existing test suite is the safety net — green CI is sufficient to consider this done.

[Ariho-Seth]

Hello @hendrikebbers, @Jexsie, this issue looks to be already done! The versions suggested in the issue description are the same versions already in the codebase.