Drop unused +indexmap feature in build-dependency on gimli

Crate gimli no longer provides this feature.

Closes: #1056695
Closes: #1060983

debian/control

@@ -7,7 +7,7 @@ Build-Depends: debhelper-compat (= 12),
                dh-cargo,
                librust-anyhow-1-dev,
                librust-fallible-iterator-0-dev,
-               librust-gimli-0+indexmap-dev (>= 0.26),
+               librust-gimli-0+default-dev (>= 0.26),
                librust-memmap-0-dev (>= 0.7),
                librust-object-0+default-dev (>= 0.29),
                librust-serde-1+derive-dev,