add alt-ergo 2.6 to the docker image #3481

Job	Run time
EasyCrypt compilation (opam)	1m 14s
EasyCrypt compilation (nix)	1m 25s
Fetch EasyCrypt External Projects Matrix	2s
Check EasyCrypt Libraries (unit)	1m 18s
Check EasyCrypt External Projects (jasmin-eclib, https://github.com/jasmin-lang/jasmin, main, ecl...	1m 51s
Check EasyCrypt Libraries (stdlib)	5m 4s
Check EasyCrypt External Projects (sha3, https://gitlab.com/easycrypt/sha3, next, ., config/tests...	12m 6s
Check EasyCrypt Libraries (examples)	3m 7s
Check EasyCrypt External Projects (cryptobox, https://gitlab.com/fdupress/ec-cryptobox, next, ., ...	2m 19s
Check EasyCrypt External Projects (xsalsa20, https://gitlab.com/fdupress/ec-xsalsa, master, ., co...	1m 44s
Check EasyCrypt External Projects (xmss-acai, https://github.com/MM45/FV-XMSS-EC, master, ., conf...	7m 46s
Check EasyCrypt External Projects (xmss-fsai, https://github.com/MM45/FV-XMSS-EC, master, ., conf...	6m 47s
Check EasyCrypt External Projects (sphincsplus, https://github.com/MM45/FV-SPHINCSPLUS-EC, master...	20m 53s
Check EasyCrypt External Projects (set-status)	1s
Notification	2s
	1h 5m 39s

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