Enable dependabot integration

[DarkWanderer]

Which problem is this PR solving?

• This PR adds Dependabot integration, which allows to semi-automatically resolve security issues related to outdated dependencies
• Helps solve [Bug]: Resolve High CVEs #123 and similar issues

Short description of the changes

• Adds dependabot.yml file which configures automatic PRs with Go dependency updates
• Dependabot will create automatic PRs with dependency updates, as well as generate security advisories
• NOTE: Additional action required on repository level to enable dependabot alerts, see https://github.com/jaegertracing/jaeger-clickhouse/security/dependabot

Example security advisories

Example PRs