Error: found in Chart.yaml, but missing in charts/ directory: mysql

I updated .helmignore

# Patterns to ignore when building packages.
# This supports shell glob matching, relative path matching, and
# negation (prefixed with !). Only one pattern per line.
.DS_Store
# Common VCS dirs
.git/
.gitignore
.bzr/
.bzrignore
.hg/
.hgignore
.svn/
# Common backup files
*.swp
*.bak
*.tmp
*~
# Various IDEs
.project
.idea/
*.tmproj
.vscode/
charts/

It contained charts/ I removed the entry and it worked

# Patterns to ignore when building packages.
# This supports shell glob matching, relative path matching, and
# negation (prefixed with !). Only one pattern per line.
.DS_Store
# Common VCS dirs
.git/
.gitignore
.bzr/
.bzrignore
.hg/
.hgignore
.svn/
# Common backup files
*.swp
*.bak
*.tmp
*~
# Various IDEs
.project
.idea/
*.tmproj
.vscode/

You don't have to add it to the control version system, you just download them again if for some reason you have lost them (for example when you clone the repository). To do this, execute the command:

helm dependency update

The above command will download the dependencies you've defined in the requirements.yaml file or dependencies entry in Chart.yaml to the charts folder. This way, requirements are updated and you'll have the correct dependencies without worrying about if you updated them also in the control version system.