Fix data location in csv example

[Gerrrr]

Without this PR:

$ docker-compose -f examples/csv/docker-compose.yaml run --build otava bin/otava analyze local.sample
...
Error response from daemon: error while creating mount source path '/Users/asorokoumov/Projects/otava/examples/csv/tests': chown /Users/asorokoumov/Projects/otava/examples/csv/tests: permission denied

With this PR:

$ docker-compose -f examples/csv/docker-compose.yaml run --build otava bin/otava analyze local.sample
...
Computing change points for test local.sample...
time                       commit      metric1    metric2
-------------------------  --------  ---------  ---------
2025-01-01 02:00:00 +0000  aaa0         154023      10.43
2025-01-02 02:00:00 +0000  aaa1         138455      10.23
2025-01-03 02:00:00 +0000  aaa2         143112      10.29
2025-01-04 02:00:00 +0000  aaa3         149190      10.91
2025-01-05 02:00:00 +0000  aaa4         132098      10.34
2025-01-06 02:00:00 +0000  aaa5         151344      10.69
                                                ·········
                                                   -12.9%
                                                ·········
2025-01-07 02:00:00 +0000  aaa6         155145       9.23
2025-01-08 02:00:00 +0000  aaa7         148889       9.11
2025-01-09 02:00:00 +0000  aaa8         149466       9.13
2025-01-10 02:00:00 +0000  aaa9         148209       9.03

[henrikingo]

Please also create a ticket about creating a new .github/workflows/*.yml that builds the docker image each time and possibly also executes a few tests.