Update ghcr.io/canastawiki/canasta Docker tag to v1.39.1

This MR contains the following updates:

Package	Type	Update	Change
ghcr.io/canastawiki/canasta	ironbank-docker	minor	1.35.8-latest -> 1.39.1-latest
ghcr.io/canastawiki/canasta		minor	1.35.8-latest -> 1.39.1-latest
ghcr.io/canastawiki/canasta	stage	minor	1.35.8-latest -> 1.39.1-latest

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