Fix Elixir 1.20 warnings, pin toolchain to 1.20.1-otp-29 & refresh deps

[gilbertwong96]

Summary

• Removes two Elixir 1.20+ compiler warnings in MissingFkIndexesLogic and MissingFkConstraintsLogic (unused require Logger — neither module references Logger, so the require is dead code).
• Pins .tool-versions to a single coherent pair: elixir 1.20.1-otp-29 + erlang 29.0.2. The previous fallback (1.16.0-otp-26 1.18 paired with 26.0.2 27.2) was incoherent: 1.18 resolves to 1.18.4-otp-28, which requires OTP 28+, so any mise install would pair it with erlang 26.0.2 and crash with Failed to load module 'elixir'. The new pair matches the toolchain already installed locally.
• Refreshes mix.lock to the dep versions required by the new toolchain (decimal 2.1.1 → 3.1.1, ecto 3.11.2 → 3.14.0, ecto_sql 3.11.3 → 3.14.0, db_connection 2.7.0 → 2.10.1, ex_doc 0.34.2 → 0.40.3, mock 0.3.8 → 0.3.9, plus patch bumps for earmark_parser, makeup, makeup_elixir, makeup_erlang, nimble_parsec) and forces meck 1.2+ via an in-project override (see follow-up commit).
• Bumps the project's stated Elixir minimum from ~> 1.11 to ~> 1.15 to honestly reflect what the locked deps now require (postgrex 0.22.x uses ^positions_bytes which is invalid on 1.14).
• Adds 1.20.1 / 29 to the CI matrix (newest first) and drops 1.14 / 25 (no longer supported by postgrex 0.22.x). Net matrix size unchanged at 6 combos.

Follow-up: why meck 1.2 is a direct dep with override: true

mock 0.3.9 (latest) pins meck ~> 0.9.2. meck 0.9.2 uses the deprecated Erlang (catch ...) expression, which is a hard compile error in OTP 28+ (removed outright). meck 1.2.0 (2026-05-27) added official OTP 29 support, but mock 0.3.9's constraint excludes it. The only way to get a newer meck is to add it as a direct dep with override: true. Marked only: :test so it never reaches a release.

Verification

• mix compile --force --warnings-as-errors → exit 0
• MIX_ENV=test mix compile --force --warnings-as-errors → exit 0

The project's own source compiles clean. The test suite requires a running PostgreSQL and is best validated by CI on the updated 6-pair matrix.

Out of scope

postgrex 0.22.2's own mix.exs still uses the deprecated xref: [exclude: [Jason]] and emits a one-line Elixir 1.20 deprecation warning during its own compilation. That's an upstream issue (latest postgrex release hasn't migrated to elixirc_options: [no_warn_undefined: ...]) and not in our project's mix.exs, so it's left alone here.

Files changed

 .github/workflows/ci.yml                                |  6 ++---
 .tool-versions                                          |  4 ++--
 lib/ecto_psql_extras/missing_fk_constraints_logic.ex    |  2 --
 lib/ecto_psql_extras/missing_fk_indexes_logic.ex        |  2 --
 mix.exs                                                 |  8 ++++++--
 mix.lock                                                | 30 ++++++++++++++++----------
 6 files changed, 24 insertions(+), 28 deletions(-)

Context

Follows the same pattern as #46 (Fix Elixir 1.15 warning, require Elixir 1.11+ & bump Ecto/Postgrex requirements) — bump the toolchain, fix any new warnings that surface, refresh the lockfile.

[pawurb]

Hi, thanks for the PRs but I currently don't have capacity to maintain this project, and I'll be archiving it. I hope that someone can fork and take over.