CI build fails: ./_scripts/install.sh: 3: ./pharo: not found



```
Run make generate
git clone -b pharo61 https://github.com/guillep/ecstatic.git .ecstatic
Cloning into '.ecstatic'...
cd .ecstatic && ./_scripts/install.sh
./_scripts/install.sh: 3: ./pharo: not found
make: *** [Makefile:3: .ecstatic] Error 127
Error: Process completed with exit code 2.
```