You can use the Bitbucket SSH URL instead of the https URL and configure SSH without a password using an SSH key.
Change your subfile:
source ' git@bitbucket.org :MyRepo/My-podspecs.git'
And follow the instructions on the BitBucket page to configure the SSH key and add it to your Bitbucket account. Make sure you give an empty password when creating your key / identity. For example, in step 3.4 of their OSX / Linux instructions, just press enter twice.
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