Update minimal version requirements for dependencies (#2460)

This was tested using cargo generate-lockfile -Zminimal-versions.
The following indirect dependencies also have minimal version
dependencies. For at least num, rustc-serialize and rand this is
necessary to compile on rustc versions that are not older than 1.0.

* num = "0.1.27"
* rustc-serialize = "0.3.20"
* termcolor = "1.0.4"
* libudev-sys = "0.1.1"
* rand = "0.3.14"
* ab_glyph = "0.2.7

Based on bevyengine/bevy#2455

Cargo.toml

@@ -29,6 +29,6 @@ bevy_log = { path = "../bevy_log", version = "0.5.0" }
 # other
 gltf = { version = "0.16.0", default-features = false, features = ["utils", "names", "KHR_materials_unlit"] }
 thiserror = "1.0"
-anyhow = "1.0"
+anyhow = "1.0.4"
 base64 = "0.13.0"
 percent-encoding = "2.1"