ci: Set Docker API version explicitly

[qezz]

Apparently Docker Engine v29 broke some compatibility with testcontainers, but setting this var should work.

[qezz]

If tests work, then it works as expected.

Broken tests were failing as:

--- FAIL: TestIsImagePresent (60.01s)
    util.go:112: 
        	Error Trace:	/home/runner/work/blazar/blazar/internal/pkg/testutils/util.go:112
        	            				/home/runner/work/blazar/blazar/internal/pkg/docker/docker_test.go:16
        	Error:      	Received unexpected error:
        	            	Error response from daemon: client version 1.43 is too old. Minimum supported API version is 1.44, please upgrade your client to a newer version
        	            	error during connect: Post "http://%2Fvar%2Frun%2Fdocker.sock/v1.43/build?buildargs=null&cachefrom=null&cgroupparent=&cpuperiod=0&cpuquota=0&cpusetcpus=&cpusetmems=&cpushares=0&dockerfile=Dockerfile&forcerm=1&labels=null&memory=0&memswap=0&networkmode=&rm=1&shmsize=0&t=img%3Atag&target=&ulimits=null&version=": io: read/write on closed pipe

[qezz]

tests failed

[qezz]

ok so setting docker version won't work, obviously, because it's testcontainers that got outdated, not docker

[qezz]

closing in favor of #63