Update exercises to use local repository rather than working off this repository

[andyfeller]

Problem

These exercises really don't need to clone or commit to this repository for participants. Instead, the instructions should be updated to allow participants to create and initialize a repository locally for use.

Acceptance Criteria

• Rethink the exercise steps in creating and populating a repository with commits, merges, and tags that need to be signed
• Update exercise to reflect new steps

[andyfeller]

The revised exercises created here are required for working on #3 since we want the illustrations to be tied to the work that is being done in the workshop.

[andyfeller]

Exercise 1 summary

git init -b main simplify-signing-with-ssh-workspace
cd simplify-signing-with-ssh-workspace
git config gpg.format ssh
git config user.signingkey "$(cat ~/.ssh/id_ed25519.pub)"
git config gpg.ssh.allowedSignersFile ~/.ssh/allowed_signers

Exercise 2 summary

cat << 'EOF' > README.md
# My git-merge-workshops/simplify-signing-with-ssh workspace

This repository is my workspace for experimenting with SSH signing keys as a part of [git-merge-workshops/simplify-signing-with-ssh](https://github.com/git-merge-workshops/simplify-signing-with-ssh) where I experimented with the following exercises:

1. [Setup workstation](https://github.com/git-merge-workshops/simplify-signing-with-ssh/blob/main/exercises/01-setup-workstation.md)
1. [Signing and verifying commits](https://github.com/git-merge-workshops/simplify-signing-with-ssh/blob/main/exercises/02-sign-verify-commits.md)
1. [Signing and verifying merges](https://github.com/git-merge-workshops/simplify-signing-with-ssh/blob/main/exercises/03-sign-verify-merges.md)
1. [Signing and verifying tags](https://github.com/git-merge-workshops/simplify-signing-with-ssh/blob/main/exercises/04-sign-verify-tags.md)
1. [Signing past commits and tags](https://github.com/git-merge-workshops/simplify-signing-with-ssh/blob/main/exercises/05-sign-past-commits-tags.md)

EOF

git add .
git commit -S -m "Initialize workspace repository README"

git config commit.gpgsign true
git config log.showSignature true

resulting in:

Exercise 3 summary

git checkout -b feature/v1.0.0

cat << 'EOF' > hello-world.sh
#! /usr/bin/env bash

echo "Hello world!"
EOF

chmod 755 hello-world.sh
./hello-world.sh

git add .
git commit -m "Adding hello-world script for v1.0.0 release"

git checkout main

cat << 'EOF' >> README.md

## Hello world!

The `v1.0.0` release contains the `hello-world.sh` script, which understandably displays `Hello world!`.
EOF

git add .
git commit -m "Expanding README for upcoming feature"

git merge --verify-signatures feature/v1.0.0 -m "Merging in work towards v1.0.0 release"

git config merge.verifySignatures true

Exercise 4 summary

git tag -s -m "Tagging v1.0.0 release" v1.0.0

git config tag.gpgsign true

Exercise 5 summary

cat << 'EOF' > foo.sh
#! /usr/bin/env bash

echo "bar"
EOF

cat << 'EOF' >> README.md

## Foo bar

Since the `v1.0.0` release, the `foo.sh` script was added, which understandably displays `bar`.
EOF

chmod 755 foo.sh
./foo.sh

git add .
git commit --no-gpg-sign -m "Adding foo script without signing"
git log

git commit --amend --no-edit -S
git verify-commit -v HEAD

git tag --no-sign -m "Setup for signing old tags" v1.1.0
git tag -v v1.1.0

git tag v1.1.0 v1.1.0 -f -s
git tag -v v1.1.0