Bump Emacs version to 26.2.90

* README:
* configure.ac:
* msdos/sed2v2.inp:
* nt/README.W32: Bump Emacs version.
1 job for emacs-26 in 9 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
failed #2119
test

00:00:09

 
Name Stage Failure
failed
test Test There has been a runner system failure, please try again
Running with gitlab-runner 11.6.0 (f100a208)
on gitlab-runner-docker cff9d373
Using Docker executor with image debian:stretch ...
Pulling docker image debian:stretch ...
Using docker image sha256:e1de74e67cc70422153600785c4ce4c29843a0e59e18b634c52ca133c564437f for debian:stretch ...
ERROR: Job failed (system failure): Error response from daemon: failed to start shim: exec: "docker-containerd-shim": executable file not found in $PATH: unknown (executor_docker.go:1018:1s)