bt-volume-step: add package

Source package for https://github.com/Felitendo/bt-volume-step: a daemon that
corrects the coarse internal volume grid of Bluetooth audio devices on
PipeWire. Nothing is compiled; the upstream Makefile installs the script and
a systemd user unit.

bt-volume-step/pkg.sh

@@ -0,0 +1,27 @@
+# bt-volume-step - fixed volume steps for Bluetooth audio devices on PipeWire
+# (https://github.com/Felitendo/bt-volume-step).
+#
+# Nothing is compiled: the payload is a single Python script plus a systemd
+# user unit, installed by the upstream Makefile. Sourced from the release
+# tarball, so this is a source package without a -bin suffix.
+
+UPSTREAM_REPO="Felitendo/bt-volume-step"
+
+# Installed in CI (pacman) before the makepkg test build. check() runs the
+# upstream test suite, which needs nothing beyond python.
+BUILD_DEPS=(python)
+
+latest_version() {
+  curl -sf "https://api.github.com/repos/$UPSTREAM_REPO/releases/latest" \
+    | jq -r '.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"
+}