ci: Install rpyc from pip instead of apt

The apt package appears outdated and incompatible with the latest version on pypi.

>>> ValueError: invalid message type: 18

.github/workflows/ci.yml

@@ -19,6 +19,13 @@ jobs:
         git fetch origin
         git log --oneline --graph -10
 
+    - name: Install RPyC for gdb
+      run: |
+        # The version packaged in python3-rpyc is too old on Ubuntu 22.04
+        sudo apt-get update && sudo apt-get install -y python3-pip gdb gdbserver
+        /usr/bin/python -m pip install rpyc
+        gdb --batch --quiet --nx --nh --ex 'py import rpyc; print(rpyc.version.version)'
+
     - name: Cache for pip
       uses: actions/cache@v4
       id: cache-pip
@@ -62,7 +69,6 @@ jobs:
         sudo apt-get update
         sudo apt-get install -y --no-install-recommends -o Acquire::Retries=3 \
           ash bash-static dash ksh mksh zsh \
-          python3-rpyc \
           gdb gdbserver socat \
           binutils-multiarch qemu-user-static \
           binutils-aarch64-linux-gnu \

pwnlib/gdb.py

@@ -526,6 +526,7 @@ def debug(args, gdbscript=None, exe=None, ssh=None, env=None, sysroot=None, api=
         >>> io = gdb.debug(["grep", "local-libc.so", "/proc/self/maps"], gdbscript="continue", env={"LD_PRELOAD": "./local-libc.so"})
         >>> io.recvline().split()[-1] # doctest: +ELLIPSIS
         b'.../local-libc.so'
+        >>> io.close()
         >>> os.remove("./local-libc.so") # cleanup
 
 
@@ -555,6 +556,7 @@ def debug(args, gdbscript=None, exe=None, ssh=None, env=None, sysroot=None, api=
         >>> io.gdb.continue_nowait()
         >>> io.recvline()
         b'foo\n'
+        >>> io.close()
 
 
     Using SSH: