Fix keyserver issues, cherry pick aaronjamt/patch-1

Dockerfile

@@ -80,9 +80,14 @@ RUN if [[ "${RANKMIRRORS}" ]]; then \
         && cat /etc/pacman.d/mirrorlist \
     ; fi
 
+# Fixes issue with invalid GPG keys: update the archlinux-keyring package to get the latest keys, then remove and regenerate gnupg keys
+RUN pacman -Sy archlinux-keyring --noconfirm && rm -rf /etc/pacman.d/gnupg && pacman-key --init && pacman-key --populate
+
 RUN tee -a /etc/pacman.d/gnupg/gpg.conf <<< 'keyserver hkp://keyserver.ubuntu.com' \
     && tee -a /etc/pacman.d/gnupg/gpg.conf <<< 'keyserver hkps://hkps.pool.sks-keyservers.net:443' \
-    && tee -a /etc/pacman.d/gnupg/gpg.conf <<< 'keyserver hkp://pgp.mit.edu:11371'
+    && tee -a /etc/pacman.d/gnupg/gpg.conf <<< 'keyserver hkp://pgp.mit.edu:11371' \
+    && tee -a /etc/pacman.d/gnupg/gpg.conf <<< 'keyserver hkps://keys.openpgp.org' \
+    && tee -a /etc/pacman.d/gnupg/gpg.conf <<< 'keyserver hkps://keys.mailvelope.com'
 
 # This fails on hub.docker.com, useful for debugging in cloud
 # RUN [[ $(egrep -c '(svm|vmx)' /proc/cpuinfo) -gt 0 ]] || { echo KVM not possible on this host && exit 1; }