[v1.9.x] Update Dockerfile.build.ubuntu_cpu_jekyll

[waytrue17]

Description

The CI website pipeline is failing when installing Jekyll: https://jenkins.mxnet-ci.amazon-ml.com/blue/organizations/jenkins/mxnet-validation%2Fwebsite/detail/PR-20626/9/pipeline/. This PR updates the dockerfile in v1.9 to the one used in the master branch, trying to fix the issue.

Checklist

Essentials

• PR's title starts with a category (e.g. [BUGFIX], [MODEL], [TUTORIAL], [FEATURE], [DOC], etc)
• Changes are complete (i.e. I finished coding on this PR)
• All changes have test coverage
• Code is well-documented

Changes

• Feature1, tests, (and when applicable, API doc)
• Feature2, tests, (and when applicable, API doc)

Comments

• If this change is a backward incompatible change, why must this change be made.
• Interesting edge cases to note here

[mxnet-bot]

Hey @waytrue17 , Thanks for submitting the PR
All tests are already queued to run once. If tests fail, you can trigger one or more tests again with the following commands:

• To trigger all jobs: @mxnet-bot run ci [all]
• To trigger specific jobs: @mxnet-bot run ci [job1, job2]

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CI supported jobs: [unix-cpu, centos-gpu, clang, sanity, edge, windows-cpu, miscellaneous, windows-gpu, unix-gpu, centos-cpu, website]

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Note:
Only following 3 categories can trigger CI :PR Author, MXNet Committer, Jenkins Admin.
All CI tests must pass before the PR can be merged.

[josephevans]

FYI - merged this into #20626

[waytrue17]

Close the PR as it was merged into #20626