fix(ci): add external_lib to docker (#29)

Description
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Motivation and Context
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How Has This Been Tested?
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What process can a PR reviewer use to test or verify this change?
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Breaking Changes
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- [x] None
- [ ] Requires data directory on base node to be deleted
- [ ] Requires hard fork
- [ ] Other - Please specify

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.dockerignore

@@ -8,6 +8,3 @@ npm-debug.log
 .git
 .gitignore
 .github
-
-# Testing external_libs
-external_libs