Drone CI job shuffling (#1359)

- Disable bionic arm64 job to reduce the load on the ARM box a bit.
- Add bionic amd64 build so that we have a (normal) build on bionic.
- Remove sid/g++-10 job because g++ is now the default on sid (so the
  debian/sid build is already doing the same thing).

.drone.jsonnet

@@ -194,14 +194,12 @@ local mac_builder(name, build_type='Release', werror=true, cmake_extra='', extra
     debian_pipeline("Debian sid/Debug (amd64)", "debian:sid", build_type='Debug', lto=true),
     debian_pipeline("Debian sid/clang-10 (amd64)", "debian:sid", deps='clang-10 '+default_deps_nocxx,
                     cmake_extra='-DCMAKE_C_COMPILER=clang-10 -DCMAKE_CXX_COMPILER=clang++-10 ', lto=true),
-    debian_pipeline("Debian sid/gcc-10 (amd64)", "debian:sid", deps='g++-10 '+default_deps_nocxx,
-                    cmake_extra='-DCMAKE_C_COMPILER=gcc-10 -DCMAKE_CXX_COMPILER=g++-10'),
     debian_pipeline("Debian buster (i386)", "i386/debian:buster", cmake_extra='-DDOWNLOAD_SODIUM=ON'),
     debian_pipeline("Ubuntu focal (amd64)", "ubuntu:focal"),
+    debian_pipeline("Ubuntu bionic (amd64)", "ubuntu:bionic", deps='g++-8 ' + default_deps_nocxx,
+                    cmake_extra='-DCMAKE_C_COMPILER=gcc-8 -DCMAKE_CXX_COMPILER=g++-8', imaginary_repo=true),
 
     // ARM builds (ARM64 and armhf)
-    debian_pipeline("Ubuntu bionic (ARM64)", "ubuntu:bionic", arch="arm64", deps='g++-8 ' + default_deps_nocxx,
-                    cmake_extra='-DCMAKE_C_COMPILER=gcc-8 -DCMAKE_CXX_COMPILER=g++-8', imaginary_repo=true),
     debian_pipeline("Debian sid (ARM64)", "debian:sid", arch="arm64"),
     debian_pipeline("Debian buster (armhf)", "arm32v7/debian:buster", arch="arm64", cmake_extra='-DDOWNLOAD_SODIUM=ON'),