Add middleclick-autoscroll

Middle-click autoscroll for every Chromium-based application on the system -
Electron and CEF applications, Chromium-based browsers, Flatpaks, Spotify and
Steam - plus anything installed later. Built from source out of the upstream
release tarball, like cachy-auto-update.

middleclick-autoscroll/pkg.sh

@@ -0,0 +1,27 @@
+# middleclick-autoscroll - middle-click autoscroll for Chromium-based
+# applications (https://github.com/Felitendo/middleclick-autoscroll).
+#
+# Pure shell plus a gettext catalog and a scdoc man page, so the PKGBUILD just
+# runs the upstream Makefile against the release tarball. Nothing is prebuilt
+# and nothing is republished - the AUR package builds exactly what the tag
+# contains.
+
+UPSTREAM_REPO="Felitendo/middleclick-autoscroll"
+
+# Installed in CI (pacman) before the makepkg test build.
+BUILD_DEPS=(gettext scdoc)
+
+latest_version() {
+  gh api "repos/$UPSTREAM_REPO/releases/latest" --jq '.tag_name' | sed 's/^v//'
+}
+
+# refresh_checksums <version> <pkgbuild-path>
+refresh_checksums() {
+  local ver="$1" pkgbuild="$2"
+  local sha
+
+  sha="$(curl -sfL "https://github.com/$UPSTREAM_REPO/archive/refs/tags/v$ver.tar.gz" \
+    | sha256sum | cut -d' ' -f1)"
+
+  sed -i "s|^sha256sums=.*|sha256sums=('$sha')|" "$pkgbuild"
+}