chore: downgrade Jest to version 26 (v14.x)

[hops-release-bot]

⚠️ This PR is the successor of #1856 and has been created automatically because the previous PR's commits could not be cherry-picked. ⚠️

Please resolve the conflicts and merge this PR afterwards by running the following command:

git fetch origin && \
git fetch origin pull/1856/head && \
git checkout downgrade-jest-v14.x && \
git reset --hard HEAD^ && \
git cherry-pick 63c8ce718d5155d1612a0f66bb621eb80650d175

After successfully resolving all conflicts, you need to force-push your changes.

git push --force origin downgrade-jest-v14.x

---

...in order to get rid of the error...

Error: [BABEL]: Reentrant plugin detected trying to load "fea/hops/node_modules/jest-preset-hops/helpers/babel-plugin-rename-corejs.js". This module is not ignored and is trying to load itself while compiling itself, leading to a dependency cycle. We recommend adding it to your "ignore" list in your babelrc, or to a .babelignore. (While processing: fea/hops/node_modules/jest-preset-hops/helpers/babel-plugin-rename-corejs.js)

...when the Jest cache is warmed

Bors merge bot cheat sheet

We are using bors-ng to automate merging of our pull requests. The following table provides a summary of commands that are available to reviewers (members of this repository with push access) and delegates (in case of bors delegate+ or bors delegate=[list]).

Syntax	Description
bors merge	Run the test suite and push to master if it passes. Short for "reviewed: looks good."
bors merge-	Cancel an r+, r=, merge, or merge=
bors try	Run the test suite without pushing to master.
bors try-	Cancel a try
bors delegate+	Allow the pull request author to merge their changes.
bors delegate=[list]	Allow the listed users to r+ this pull request's changes.
bors retry	Run the previous command a second time.

This is a short collection of opinionated commands. For a full list of the commands read the bors reference.

[herschel666]

bors merge

[bors]

Build succeeded:

• canarist/internal-hops
• canarist/internal-workshop
• tests (12.x)
• tests (14.x)
• tests (15.x)