dev_scripts: Handle Dangerzone packages with patch level != 1

Update our `env.py` script to auto-detect the correct Dangerzone package
name. This is useful when building an end-user environment, i.e., a
container image where we copy the respective Dangerzone .deb/.rpm
package and install it via a package manager.

To achieve this, we replace the hardcoded patch level (`-1`) in the
package name with a glob character (`*`). Then, we check in the
respective build directory if there's exactly one match for this
pattern. If yes, we return the full path. If not, we raise an exception.

Note that this limitation was triggered when we were building RPM
packages for the 0.7.0 hotfix release.

Refs #880

dev_scripts/env.py

@@ -411,6 +411,28 @@ def from_args(cls, args):
         """Create an Env class from CLI arguments"""
         return cls(distro=args.distro, version=args.version, runtime=args.runtime)
 
+    def find_dz_package(self, path, pattern):
+        """Get the full path of the Dangerzone package in the specified dir.
+
+        There are times where we don't know the exact name of the Dangerzone package
+        that we've built, e.g., because its patch level may have changed.
+
+        Auto-detect the Dangerzone package based on a pattern that a user has provided,
+        and fail if there are none, or multiple matches. If there's a single match, then
+        return the full path for the package.
+        """
+        matches = list(path.glob(pattern))
+        if len(matches) == 0:
+            raise RuntimeError(
+                f"Could not find Dangerzone package '{pattern}' in '{path}'"
+            )
+        elif len(matches) > 1:
+            raise RuntimeError(
+                f"Found more than one matches for Dangerzone package '{pattern}' in"
+                f" '{path}'"
+            )
+        return matches[0]
+
     def runtime_run(self, *args):
         """Run a command for a specific container runtime.
 
@@ -610,8 +632,9 @@ def build(
         version = dz_version()
         if self.distro == "fedora":
             install_deps = DOCKERFILE_BUILD_FEDORA_DEPS
-            package = f"dangerzone-{version}-1.fc{self.version}.x86_64.rpm"
-            package_src = git_root() / "dist" / package
+            package_pattern = f"dangerzone-{version}-*.fc{self.version}.x86_64.rpm"
+            package_src = self.find_dz_package(git_root() / "dist", package_pattern)
+            package = package_src.name
             package_dst = build_dir / package
             install_cmd = "dnf install -y"
 
@@ -652,8 +675,9 @@ def build(
                 "noble",
             ):
                 install_deps = DOCKERFILE_UBUNTU_REM_USER + DOCKERFILE_BUILD_DEBIAN_DEPS
-            package = f"dangerzone_{version}-1_all.deb"
-            package_src = git_root() / "deb_dist" / package
+            package_pattern = f"dangerzone_{version}-*_all.deb"
+            package_src = self.find_dz_package(git_root() / "deb_dist", package_pattern)
+            package = package_src.name
             package_dst = build_dir / package
             install_cmd = "apt-get update && apt-get install -y"