Add support for multiple exporters

[blampe]

Buildkit 0.13 introduced support for multiple exporters. We currently return an error in these situations.

Instead, inspect the builder's version when loading the node and relax this error if we see it's running at least 0.13.

Fixes https://github.com/pulumi/pulumi-docker-build/issues/21.

[github-actions[bot]]

Does the PR have any schema changes?

Looking good! No breaking changes found. No new resources/functions.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 82.60870% with 8 lines in your changes missing coverage. Please review.

Project coverage is 88.05%. Comparing base (06cf6ec) to head (5a6b244). Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
provider/internal/host.go	75.00%	2 Missing and 2 partials :warning:
provider/internal/cli.go	0.00%	2 Missing :warning:
provider/internal/image.go	92.30%	1 Missing and 1 partial :warning:

Additional details and impacted files

| [Files with missing lines](https://app.codecov.io/gh/pulumi/pulumi-docker-build/pull/235?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pulumi) | Coverage Δ | | |---|---|---| | [provider/internal/client.go](https://app.codecov.io/gh/pulumi/pulumi-docker-build/pull/235?src=pr&el=tree&filepath=provider%2Finternal%2Fclient.go&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pulumi#diff-cHJvdmlkZXIvaW50ZXJuYWwvY2xpZW50Lmdv) | `85.99% <ø> (ø)` | | | [provider/internal/provider.go](https://app.codecov.io/gh/pulumi/pulumi-docker-build/pull/235?src=pr&el=tree&filepath=provider%2Finternal%2Fprovider.go&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pulumi#diff-cHJvdmlkZXIvaW50ZXJuYWwvcHJvdmlkZXIuZ28=) | `90.78% <100.00%> (ø)` | | | [provider/internal/cli.go](https://app.codecov.io/gh/pulumi/pulumi-docker-build/pull/235?src=pr&el=tree&filepath=provider%2Finternal%2Fcli.go&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pulumi#diff-cHJvdmlkZXIvaW50ZXJuYWwvY2xpLmdv) | `85.82% <0.00%> (-2.07%)` | :arrow_down: | | [provider/internal/image.go](https://app.codecov.io/gh/pulumi/pulumi-docker-build/pull/235?src=pr&el=tree&filepath=provider%2Finternal%2Fimage.go&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pulumi#diff-cHJvdmlkZXIvaW50ZXJuYWwvaW1hZ2UuZ28=) | `89.72% <92.30%> (+0.97%)` | :arrow_up: | | [provider/internal/host.go](https://app.codecov.io/gh/pulumi/pulumi-docker-build/pull/235?src=pr&el=tree&filepath=provider%2Finternal%2Fhost.go&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pulumi#diff-cHJvdmlkZXIvaW50ZXJuYWwvaG9zdC5nbw==) | `69.47% <75.00%> (+4.35%)` | :arrow_up: | ------ [Continue to review full report in Codecov by Sentry](https://app.codecov.io/gh/pulumi/pulumi-docker-build/pull/235?dropdown=coverage&src=pr&el=continue&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pulumi). > **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pulumi) > `Δ = absolute (impact)`, `ø = not affected`, `? = missing data` > Powered by [Codecov](https://app.codecov.io/gh/pulumi/pulumi-docker-build/pull/235?dropdown=coverage&src=pr&el=footer&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pulumi). Last update [06cf6ec...5a6b244](https://app.codecov.io/gh/pulumi/pulumi-docker-build/pull/235?dropdown=coverage&src=pr&el=lastupdated&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pulumi). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pulumi).