ytt converts floating point numbers to integers

**What steps did you take:**

`ytt` appears to convert input floats to integers, for example, running the command below:

echo 1.0 | ytt --file=-

I am passing `ytt` a single floating point number - 1.0 - encoded as YAML.

**What happened:**

The output from `ytt` is an integer:

1

**What did you expect:**

I expected the output to be a float:

1.0

**Anything else you would like to add:**

I understand that integer and floating point data types differ in the YAML spec. This is a simplified example from input to an application. That application behaves differently if its YAML input contains an integer or a float. In the actual use case these numbers are embedded inside more complex structures.

**Environment:**

Version:

```
% ytt --version
ytt version 0.45.0
```

OS Fedora Linux 26 on AMD 64.

/etc/os-release

```
NAME="Fedora Linux"
VERSION="36 (Workstation Edition)"
ID=fedora
VERSION_ID=36
VERSION_CODENAME=""
PLATFORM_ID="platform:f36"
PRETTY_NAME="Fedora Linux 36 (Workstation Edition)"
ANSI_COLOR="0;38;2;60;110;180"
LOGO=fedora-logo-icon
CPE_NAME="cpe:/o:fedoraproject:fedora:36"
HOME_URL="https://fedoraproject.org/"
DOCUMENTATION_URL="https://docs.fedoraproject.org/en-US/fedora/f36/system-administrators-guide/"
SUPPORT_URL="https://ask.fedoraproject.org/"
BUG_REPORT_URL="https://bugzilla.redhat.com/"
REDHAT_BUGZILLA_PRODUCT="Fedora"
REDHAT_BUGZILLA_PRODUCT_VERSION=36
REDHAT_SUPPORT_PRODUCT="Fedora"
REDHAT_SUPPORT_PRODUCT_VERSION=36
PRIVACY_POLICY_URL="https://fedoraproject.org/wiki/Legal:PrivacyPolicy"
SUPPORT_END=2023-05-16
VARIANT="Workstation Edition"
VARIANT_ID=workstation

```

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Start by reproducing the reported command, `echo 1.0 | ytt --file=-`, and compare its output with the expected `1.0`. Trace the YAML input and output handling to determine where the float becomes an integer; done means preserving the float representation in simple values and nested YAML structures.

Written by the indexing model from the issue text.