create justfile and add some scripts to it

justfile

@@ -0,0 +1,44 @@
+_default:
+    @just -l --unsorted
+
+install:
+    git submodule update
+    make package
+    code --install-extension kanata.vsix
+
+# Updates kanata to latest git + adds notice about it to CHANGELOG.md
+bump_kanata:
+    #!/bin/sh
+    set -euxo pipefail
+    git submodule update --remote
+    cd kanata
+    HASH=$(git rev-parse --short HEAD)
+    cd ..
+    # Exit early without updating changelog if a bump notice was already added in "Unreleased" section.
+    ! grep -q "$HASH" CHANGELOG.md
+    awk '/^### [0-9]/ && found==0 {found=1} found==0 && /Updated kanata to/ {next} 1' CHANGELOG.md > temp && mv temp CHANGELOG.md
+    just _add_to_changelog "Updated kanata to \[$HASH\]\(https\:\/\/github\.com\/jtroo\/kanata\/tree\/$HASH\)"
+
+# Bumps version number, pushes a "new version" commit/tags, builds, uploads to VS Code marketplace.
+release VERSION:
+    just _ensure_clean_directory
+
+    git checkout main
+    git pull
+    git checkout -b release-v{{VERSION}}
+    sed -i 's/\"version\": \"[^\"]*\"/\"version\": \"{{VERSION}}\"/' package.json
+    sed -i 's/### Unreleased/### Unreleased\n\n* no changes yet\n\n### {{VERSION}}/' CHANGELOG.md
+    git commmit -m "Release v{{VERSION}}"
+    git push origin release-v{{VERSION}}
+
+    git tag v{{VERSION}}
+    git push --tags
+
+    vsce publish {{VERSION}}
+
+_add_to_changelog TEXT:
+    sed -i '/no changes yet/Id' CHANGELOG.md
+    sed -i "N;s/^### Unreleased\n/\0\n\* {{TEXT}}/" CHANGELOG.md
+
+_ensure_clean_directory:
+    git diff-index --quiet HEAD --