Hotfix helm variable naming conventions

[tobiasrdm]

This pull request hotfix the converter to adapt to Helm variables naming conventions:
Variable names should begin with a lowercase letter, and words should be separated with camelcase.

It will convert JOB_NAME to value jobName instead of job_name.

Before:

template2helm convert --template ./examples/slack-notify-job-template.yml --chart ~/tmp/charts
Creating a template for object CronJob
Convert parameter JOB_NAME to value .job_name
Convert parameter SLACK_HOOKS_URL to value .slack_hooks_url
Convert parameter MESSAGE to value .message
Convert parameter SCHEDULE to value .schedule
Convert parameter SUCCESS_JOBS_HISTORY_LIMIT to value .success_jobs_history_limit
Convert parameter FAILED_JOBS_HISTORY_LIMIT to value .failed_jobs_history_limit

After:

template2helm convert --template ./examples/slack-notify-job-template.yml --chart ~/tmp/charts
Creating a template for object CronJob
Convert parameter JOB_NAME to value .jobName
Convert parameter SLACK_HOOKS_URL to value .slackHooksUrl
Convert parameter MESSAGE to value .message
Convert parameter SCHEDULE to value .schedule
Convert parameter SUCCESS_JOBS_HISTORY_LIMIT to value .successJobsHistoryLimit
Convert parameter FAILED_JOBS_HISTORY_LIMIT to value .failedJobsHistoryLimit