[FIX] Ensure encoding when reading boilerplate

[alioco]

Changes proposed in this pull request

Fix for error in generate_report function encountered when running singularity image of fmriprep version 1.1.8 on a cluster, with singularity version 2.6.0 raised in issue #1313.

Fixes #1313.

Documentation that should be reviewed

The flag encoding='UTF-8’ was added for all read_text and write_text functions.

[welcome]

Thanks for opening this pull request! We have detected this is the first time for you to contribute to fMRIPrep. Please check out our contributing guidelines.
We invite you to list yourself as a fMRIPrep contributor, so if your name is not already mentioned, please modify the .zenodo.json file with your data right above Russ' entry. Example:

{
   "name": "Contributor, New FMRIPrep",
   "affiliation": "Department of fMRI prep'ing, Open Science Made-Up University",
   "orcid": "<your id>"
},
{
   "name": "Poldrack, Russell A.",
   "affiliation": "Department of Psychology, Stanford University",
   "orcid": "0000-0001-6755-0259"
},

Of course, if you want to opt-out this time there is no problem at all with adding your name later. You will be always welcome to add it in the future whenever you feel it should be listed.

[oesteban]

Hi @alioco, are you planning on adding your name to the zenodo file or you'd rather opt out this time?

I'll merge as soon as I have an answer.

Thanks a lot for your contribution!

[alioco]

@oesteban I'll opt out at this time, thank you!