poppler: upgrade 21.07.0 -> 21.08.0

Release 21.08.0:
        core:
         * Add API to allow addition and modification of outlines into a PDF
         * Use additional samples to test for constant parts of an axial gradient
         * forms: Create fallback fonts for some well known font names
         * Support reading the PDF Version from the Catalog
         * Fix XRef::copy when there are modified objects
         * Take into account that Date string may be in unicode
         * JBIG2Stream: Fix regression in "Do not consider a size-0 to be an error"
         * Replace a local bubble sort implementation by std::sort
         * Fix issues with malformed files

        build system:
         * Better error message when libjpeg is not found
         * Better error messages when libopenjpeg2 is not found

        qt5/qt6:
         * Document that a document has to outlive its pages
         * Make getPdfVersion return a dedicated version object

        glib:
         * mimick TextSelectionDumper logic change for spaceAfter

Signed-off-by: Zheng Ruoqin <zhengrq.fnst@fujitsu.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>

meta-oe/recipes-support/poppler/poppler_21.08.0.bb

@@ -7,7 +7,7 @@ SRC_URI = "http://poppler.freedesktop.org/${BP}.tar.xz \
            file://0001-Do-not-overwrite-all-our-build-flags.patch \
            file://basename-include.patch \
            "
-SRC_URI[sha256sum] = "e26ab29f68065de4d6562f0a3e2b5435a83ca92be573b99a1c81998fa286a4d4"
+SRC_URI[sha256sum] = "e9cf5dc5964bce4bb0264d1c4f8122706c910588b421cfc30abc97d6b23e602d"
 
 DEPENDS = "fontconfig zlib cairo lcms glib-2.0"