Adapt solenv/flatpak-manifest.in to recent download.lst changes

(cherry picked from commit 5c016d6a)
Conflicts:
	solenv/flatpak-manifest.in

Change-Id: I7799abe1a6fc9cf79a751d76360ea7ad2face133
Reviewed-on: https://gerrit.libreoffice.org/57981Reviewed-by: Michael Stahl <Michael.Stahl@cib.de>
Tested-by: Michael Stahl <Michael.Stahl@cib.de>
(cherry picked from commit b36c5676)

solenv/flatpak-manifest.in

@@ -405,10 +405,10 @@
                     "dest-filename": "external/tarballs/liborcus-0.13.3.tar.gz"
                 },
                 {
-                    "url": "https://dev-www.libreoffice.org/src/poppler-0.59.0.tar.xz",
-                    "sha256": "a3d626b24cd14efa9864e12584b22c9c32f51c46417d7c10ca17651f297c9641",
+                    "url": "https://dev-www.libreoffice.org/src/poppler-0.66.0.tar.xz",
+                    "sha256": "2c096431adfb74bc2f53be466889b7646e1b599f28fa036094f3f7235cc9eae7",
                     "type": "file",
-                    "dest-filename": "external/tarballs/poppler-0.59.0.tar.xz"
+                    "dest-filename": "external/tarballs/poppler-0.66.0.tar.xz"
                 },
                 {
                     "url": "https://dev-www.libreoffice.org/src/c0b4799ea9850eae3ead14f0a60e9418-postgresql-9.2.1.tar.bz2",