[ci] Pin fedora 33 docker image

g-ir-scanner is broken on 34 image:

FAILED: src/HarfBuzz-0.0.gir
/usr/bin/g-ir-scanner --no-libtool --namespace=HarfBuzz --nsversion=0.0 --warn-all --output src/HarfBuzz-0.0.gir --c-include=hb-gobject.h --cflags-begin -DHB_NO_SINGLE_HEADER_ERROR -DHAVE_GOBJECT -DHB_EXTERN= --cflags-end -I/root/project/src -I/root/project/build/src -I./. -I../. --filelist=/root/project/build/src/libharfbuzz-gobject.so.0.20800.0.p/HarfBuzz_0.0_gir_filelist --include=GObject-2.0 --symbol-prefix=hb --symbol-prefix=hb_gobject --identifier-prefix=hb_ --pkg-export=harfbuzz-gobject --cflags-begin -DHAVE_CONFIG_H -I./. -I../. -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/include/sysprof-4 -I./src/. -I../src/. -I/usr/include/freetype2 -I/usr/include/libpng16 -I/usr/include/harfbuzz -I/usr/include/gobject-introspection-1.0 --cflags-end --add-include-path=/usr/share/gir-1.0 -L/root/project/build/src --extra-library=harfbuzz --library harfbuzz-gobject -L/root/project/build/src -L/root/project/build/src --extra-library=glib-2.0 --extra-library=gobject-2.0 --extra-library=m --extra-library=freetype --extra-library=girepository-1.0 --sources-top-dirs /root/project/subprojects/ --sources-top-dirs /root/project/build/subprojects/
../src/hb-buffer.cc:641: Warning: HarfBuzz: unknown annotation: xconstructor
../src/hb-face.cc:192: Warning: HarfBuzz: unknown annotation: xconstructor
../src/hb-font.cc:551: Warning: HarfBuzz: unknown annotation: xconstructor
../src/hb-font.cc:1519: Warning: HarfBuzz: unknown annotation: xconstructor
../src/hb-map.cc:43: Warning: HarfBuzz: unknown annotation: xconstructor
../src/hb-ot-name.cc:55: Warning: HarfBuzz: unexpected annotation: out
../src/hb-set.cc:43: Warning: HarfBuzz: unknown annotation: xconstructor
../src/hb-shape-plan.cc:173: Warning: HarfBuzz: unknown annotation: xconstructor
../src/hb-shape-plan.cc:201: Warning: HarfBuzz: unknown annotation: xconstructor
../src/hb-unicode.cc:172: Warning: HarfBuzz: unknown annotation: xconstructor
g-ir-scanner: link: gcc -pthread -o /root/project/build/tmp-introspecta9rymai3/HarfBuzz-0.0 /root/project/build/tmp-introspecta9rymai3/HarfBuzz-0.0.o -L. -Wl,-rpath,. -Wl,--no-as-needed -L/root/project/build/src -Wl,-rpath,/root/project/build/src -L/root/project/build/src -Wl,-rpath,/root/project/build/src -L/root/project/build/src -Wl,-rpath,/root/project/build/src -lharfbuzz-gobject -lharfbuzz -lglib-2.0 -lgobject-2.0 -lm -lfreetype -lgirepository-1.0 -lgio-2.0 -lgobject-2.0 -Wl,--export-dynamic -lgmodule-2.0 -pthread -lglib-2.0 -lglib-2.0
ldd: error: you do not have read permission for `/root/project/build/tmp-introspecta9rymai3/HarfBuzz-0.0'
Traceback (most recent call last):
  File "/usr/bin/g-ir-scanner", line 99, in <module>
    sys.exit(scanner_main(sys.argv))
  File "/usr/lib64/gobject-introspection/giscanner/scannermain.py", line 599, in scanner_main
    shlibs = create_binary(transformer, options, args)
  File "/usr/lib64/gobject-introspection/giscanner/scannermain.py", line 428, in create_binary
    shlibs = resolve_shlibs(options, binary, options.libraries)
  File "/usr/lib64/gobject-introspection/giscanner/shlibs.py", line 170, in resolve_shlibs
    _resolve_non_libtool(options, binary, non_libtool))
  File "/usr/lib64/gobject-introspection/giscanner/shlibs.py", line 106, in _resolve_non_libtool
    output = subprocess.check_output(args)
  File "/usr/lib64/python3.9/subprocess.py", line 424, in check_output
    return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
  File "/usr/lib64/python3.9/subprocess.py", line 528, in run
    raise CalledProcessError(retcode, process.args,
subprocess.CalledProcessError: Command '['ldd', '/root/project/build/tmp-introspecta9rymai3/HarfBuzz-0.0']' returned non-zero exit status 1.
ninja: build stopped: subcommand failed.

.circleci/config.yml

@@ -76,7 +76,7 @@ jobs:
 
   fedora-valgrind:
     docker:
-      - image: fedora
+      - image: fedora:33
     steps:
       - checkout
       - run: dnf install -y pkg-config ragel valgrind gcc gcc-c++ meson git glib2-devel freetype-devel cairo-devel libicu-devel gobject-introspection-devel graphite2-devel redhat-rpm-config python python-pip || true